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Biomembranes And Cell Wall

The plasma membrane and intracellular membranes collectively constitute biological membranes.

• The plasma membrane surrounds each cell, defining its limits and maintaining essential separations between its internal components and the external environment. It exhibits selective permeability.
• Intracellular membranes partition the cell into functionally distinct compartments known as organelles, including mitochondria and chloroplasts.
• Biological membranes demonstrate selective permeability, permitting the passage of some molecules while inhibiting others.
• All biological membranes display dynamism.
• All biological membranes of eukaryotic cells have fundamental architecture, comprising lipids and protein molecules interconnected by non-covalent interactions.
• Chemical composition. The plasma membrane consists of 58% proteins, encompassing structural and functional proteins like permeases, and 40% lipids, mostly phospholipids, cholesterol, and galactolipids.
• Minor polymers of monosaccharides (L-27%) form weak interactions with proteins and lipids.

Function and Structure of Cell Wall Membrane For NEET Models Of The Structure Of Plasma Membrane

The plasma membrane under an electron microscope appears to be trilaminar. Davson and Danielli put forward the Lamellar model which states that it is formed of four layers i.e. two proteins and two phospholipids. J.D. Robertson gave the concept of unit membrane which means that all membranes have three layers with a phospholipid bilayer sandwiched between two layers of proteins.

Read and Learn More NEET Biology Notes

According to the unit-membrane concept, all cell membranes possess a common basic structure, consisting of two layers of proteins and a middle bilayer of lipids. According to the fluid-mosaic model, the lipids and proteins are managed in a mosaic fashion in the membrane.

The cell membrane possesses a quasi-fluid phospholipid layer with embedded proteins. These impart considerable fluidity to the membranes.

Singer and Nicholson proposed a Fluid mosaic model. According to this model, phospholipids are arranged in a bimolecular layer with their hydrophilic polar heads forming outer surfaces and hydrophobic non-polar tails buried in the membrane.

The proteins are extrinsic and intrinsic. The plasma membrane is in the form of quasi-fluid. It also explains the permeability of carrier proteins.

Detailed Notes On Cell Wall And Cell Membrane Structure For NEET

Specialization of the plasma membrane. Various modifications are formed to perform special functions. They are microvilli. The adjacent cells may develop specialized structures such as interdigitations, desmosomes, intermediary junctions, and tight junctions.

Functions. lt provides shape and protects the contents inside the cell.

It controls permeation and has the property of retentivity. It binds the semifluid cellular constituents. It also acts as a barrier between protoplasm and the external environment. It possesses properties of permeability, and surface tension and is electrically charged.

Function and Structure of Cell Wall Membrane For NEET Flow Of Materials

To perform the various life activities, the cell must exchange certain substances with the environment.

It is necessary that metabolic essentials such as oxygen mineral salts and nutrients must get into the cell and waste products such as ammonia, COr, calcium crystals, and other metabolites, must pass out of the cell.

All these exchanges can take place only through the cell membrane by many processes as follows:

1. Passive transport
   • Diffusion
   • Osmosis
2. Facilitated diffusion
3. Active transport
4. Na+ and K+ exchange Pump
5. Endocytosis
   • Phagocytosis
   • Pinocytosis
6. Exocytosis

Transport of materials takes place across the membranes by two major processes-

Passive Transport and Active Transport. Passive transport is a physical process that neither requires energy nor oxygen for the transport of substances by the cell. This includes diffusion and osmosis’

Diffusion. The physical process involves the transport of materials from a region of higher concentration to a region (solutes and gases) of lower concentration and pressure respectively to spread uniformly.

Facilitated diffusion. A substance first combines with the carrier protein without the use of energy in the cell membrane and then it diffuses across the membrane.

The diffusion rate can be expressed by the formula:

Diffusion rate = Concentration difference x Cross-sectional area x Temperature/\tlolecular

weight x Distance x Density of Medium.

Osmosis. Bulk flow of water through a semipermeable membrane into another aqueous phase containing a solute in higher concentration Osmotic pressure.

Pressure is generated by the osmotic flow of water through a membrane into an aqueous phase containing a solute in higher concentration.

Important Questions On Cell Wall And Cell Membrane For NEET Exam

Plasmolysis. A plant cell when placed in hypertonic solution undergoes the shrinkage of its cytoplasm with plasma membrane.

Plants can absorb water through osmosis Active transport is an energy-dependent process.

A membrane protein acts as a carrier that binds and transports the molecule or ion in a specific direction across the membrane It even takes place against an electrochemical gradient.

In sodium-potassium exchange pump Na+ – K+ ATPase actively transports three molecules of Na+ outwards and two molecules of K+ inward.

Endocytosis. Intaking of large-sized liquid or solid macromolecules inside the cell through the plasma membrane.

Exocytosis. (cell vomiting). Expelling of cellular secretions of gland cells or wastes out of the cell through the plasma membrane.

Phagocytosis (cell-eating). Ingestion of solid particles by the cell Phagocytosis is of two kinds viz.

Colloidopexy: In this case plasma membrane ingests small colloidal particles as shown by leucocytes and macrophage cells of mammals.

Chromopexy Colloidal chromogen particles are ingested by plasma membrane as shown by mesoblastic cells of mammals.

Pinocytosis is the process of endocytosis in which liquid food is engulfed in bulk through a plasma membrane.

Plant cells possess cell walls and this feature distinguishes them from animal cells.

The cell wall is partially non-living and partially living structure. It is secreted by cytoplasm or protoplast. It has a supportive and protective function.

There are three distinct layers -middle lamella, primary cell wall, and secondary cell wall. Occa- a tertiary cell wall may be present.

‘u’ Middle lamella is a cementing layer between the primary walls of adjacent cells. It is composed of pectin, calcium, and magnesium. During the ripening of fruits enzyme pectinase dissolves it.

The primary cell wall is 0.1pm thick. It is composed of chiefly cellulose, hemicellulose, and pectic compounds. Cellulose fibrils are made up of 8,000 to 12,000 glucose units, they are about 1004 in diameter.

The secondary wall is laid down inner to the primary wall. It is 5 to 10 pm thick.

The secondary cell wall has three layers- outer layer, middle layer, and inner layer. The primary wall has small pores called plasmodesmata which connect the cytoplasm of adjacent cells. The cell wall is made up of matrix and microfibrils.

Molecular organization. The cell wall appears to consist of a gelatinous amorphous matrix consisting of polysaccharides (mainly pectin), gums, tannins, silica, and wax.

In the matrix are found many fibrils called microfibrils. 0.5 pm in width visible under a light microscope. The microfibril consists of bundles of 250 each, which is about 250 i in diameter. It is visible under an electron microscope.

The microfibril in turn consists of bundles of micelles elementary fibrils each about 100 i in diameter. The micelle contains about 100 cellulose chains.

Each microfibril is lpm long and 100-250 i in diuter. Each microfibrilconsists of 20 micelles. Each micelle consists of 100 individual cellulose chains. Each cellulose chain consists of 3000 – 6000 glucose molecules linked by B 1-4 linkage and is unbranched.

Origin. The cell wall is laid during the telophase stage of cell division from vesicles of the Golgi complex or E.R.

Function. The cell wall is a highly active region as many enzymatic activities are known to occur. In addition to providing shape and strength, it protects the cell organelles and plays a vital role in cell expansion. It helps in the transport of materials and metabolites in and out of the cell and encounters the turgor pressure developed inside.

• Most of the prokaryotic cells particularly bacterial cells, have a chemically complex cell envelope. Its layers are stacked upon one another.
• The outermost layer is glycocalyx followed by cell wall and cell membrane (plasma membrane).
• Glycocalyx. Any coat present outside the plasma membrane is called a cell coat. It forms a cell wall in plant cells and a pellicle in prokaryotes. In animal cells polysaccha- rides form the external cell coat or glycocalyx. This layer of glycocalyx differs in thickness and chemical composition in different bacteria. Some have a loose sheath called a slime layer which protects the cells from loss of nutrients and water. Some others have a tough covering called the capsule.
• In bacterial cells, the cell coat is formed of a protein-lipid polysaccharide complex.
• Bacteria can be classified according to their ability to take up and retain certain dyes.
• Gram staining is the most widely used staining procedure.
• The gram staining technique divides most bacteria into one or two groups.
• A Danish physician, Dr. Hans Christian Gram developed this staining method in 1884 to distinguish between the bacteria that cause pneumonia and eukaryotic cell nuclei in infected mammalian tissues.
• Differences between Gram-positive and Gram-negative Bacteria
• In Mycobacterium and Noccardia, the wall is of Gram-positive type but a part of their cell wall is made up of a very long chain of fatty acid called mycoic acid.
• Differences between pilus and fimbriae The Primary cell wall in plant cells is composed of an intricate network of microfibrils in a gel-like matrix arranged in cellulose microfibrils, pectic polysaccharides, and structural proteins.
• A new class of protein called expansion is responsible for wall loosening and cell expansion by the addition of cellulose molecules to cellulose microfibrils.
• The matrix of the wall contains water, pectin, hemicellulose, and glycoproteins. Pectin is the filler substance of the matrix. It is a mixture of polymerized and methylated galacturans, galacturonic acid, and neutral sugars.
• Glycoproteins control the orientation of microfibrils. They also exert enzymatic influence on the metabolic activities of the wall. Hemicellulose is a mixture of polymerized xylans, mannans, glucomannans, galactans, and arabinogalactans. It binds microfibrils with the matrix.
• The phospholipids and integral proteins of the plasma membrane are amphipathic. The term was coined by Hartley in 1936 for those molecules which have both hydrophobic and hydrophilic groups.
• The flexibility of the cell membrane is due to the presence of fatty acid contents. This enables bacteria to maintain the same fluidity over a temperature range of almost 100. c.
• The proteins are not easily extricated from the membrane because of their high degree of insolubility and non-covalent bonds.
• The plasmodesmata help in maintaining the continuity of living matter and cytoplasm, such condition is called sym-plasm. In contrast to this, the intercellular space containing non-living matter is called apoplasm.

Cell Wall And Cell Membrane Structure NEET Important Diagrams

Quanta To Memory

• Membrane-less cell organelles include ribosomes, centrioles, centrosomes, nucleoli, microtubules, microfilaments, chromosomes, and intermediate filaments.
• Cell organelles characterized by a single membrane: lysosomes, Golgi apparatus, endoplasmic reticulum, thylakoids, peroxisomes, protoplasts, vacuoles, glyoxisomes, flagella, and cilia.
• Cell organelles have a double membrane: plastids, mitochondria, nucleus.
• Cell organelles possessing many membrane layers exceeding two.
• Tranosome — three membrane encasement.
• The plastids of Euglenoids and Dinoflagellates possess three membrane layers.
• Diatom plastids possess four membrane layers.
• The typical thickness of the plasma membrane is from 70 to 100 Å, but the plasma membrane of red blood cells measures 215 Å.
• The dimensions of molecules capable of traversing the plasma membrane range from 1 to 15 angstroms.
• The nuclear membrane creates outpockets that are constricted to produce blebs or vesicles, a phenomenon known as blebbing, as reported by Gay in Drosophila.
• The most intricate glycolipids are gangliosides, which incorporate one or more sialic acid residues, also referred to as N-acetyl neuraminic acid (NANA). It imparts a negative charge to the cell membrane.
• Glycoproteins facilitate cellular recognition. A membrane is predominantly maintained by hydrophobic interactions.
• The glycocalyx is an extracellular coating located outside the cell membrane in animal cells. It comprises oligosaccharides linked to lipids and proteins, resulting in glycolipids and glycoproteins. It serves a protective function and operates as a recognition hub.
• Lipid-soluble compounds traverse the plasma membrane more easily than water-soluble molecules.
• Protein-free lipid bilayers exhibit impermeability to ions while allowing unrestricted permeability to water.
• The secretion of neurotransmitters by neurons exemplifies exocytosis.
• Seagulls and penguins excrete NaCl via nasal glands containing Na+ – K+ pumps.
• Younger cells possess thinner and elastic (semi-rigid) cell walls to facilitate growth by intussusception.
• Meristematic, parenchymatous cells, and root hairs possess solely primary cell walls

Matrix is an amorphous, gel-like material. It has watery hemicellulose and pectin but also has lipids and protein. Hemicellulose is made of:

• Arabinose
• Mannose
• Pectin consists of glucuronic acid and galacturonic acid units.
• The tertiary wall is made of cellulose and xylan.
• Plasmodesmata are inner cytoplasmic strands.
• Ca++ cross-links play a role in holding cell wall components together.
• The cell wall is permeable as spaces of framework allow free passage of dissolved materials between cells and their environment. The cell coat is different from the cell wall.
• Water moves passively through the apoplast which gives thermo- charge.
• Messenger recognition sites of two neighboring cells may bind to each other causing cell adhesion.
• Glycophorin is present in the membrane of RBC.
• In Immune responses of various response systems, glycoproteins act as antigens.
• Lipid molecules have kinks in fatty acid tails which prevent the close packing of molecules and make the membrane structure more fluid. Fluidity increases, decreasing the length of fatty acid tails. Kinks are due to double bonds in the tail.
• Carbohydrates are attached to the polar side of the lipid to form Glyeolipid 1 he lipid: Protein ratio in some eases aw as under
  • 40: 60
  • 35: 65
  • 42: 58
  • 76: 24

Functions of proteins in Plasma membrane

• Transporters of molecules across cellular membranes.
• Receptors. Information transfer within cells.
• Enzymes. Each membrane contains enzyme molecules designated for specific cellular functions.
• The plasma membrane does not permit the escape of the cell’s contents, as it retains its color due to the presence of pigment molecules.
• Gases have the highest rate of diffusion. Ions and diminutive polar molecules disperse at a sluggish rate. Fat-soluble molecules have the highest rate of passage.
• Daniel and Davson’s model was proposed prior to the observation of the plasma membrane using an electron microscope.
• The fluid mosaic concept posits that the bilayer of phospholipid molecules acts as a relatively impermeable barrier to the transit of most water-soluble substances.
• It is proposed that water exists within the plasma membrane. In the absence of water, how do lipids develop hydrophilic and hydrophobic regions? Only recommended
• Plasma membrane organelles perform analogous activities due to their fundamental structural similarities. Nonetheless, many membranes exhibit numerous structural and physicochemical functional disparities.
• The ratio of lipids to proteins ranges from 1:08 to 1:4. The unit membrane idea cannot be applied unconditionally.
• The lignified wall is colored with safranin. The cell wall is lacking in mycoplasma, gametes, and animal cells.

Animal Kingdom Non-Chordate Phyla Classification Of Animal Kingdom

There are about 1.2 million animal species which show a great diversity of life. Though the animals are metazoans like the plants they differ from plants in several characteristics like the absence of plastids, cell wall, and central vacuole; and having centrosomes in the cells.

These are exclusively heterotrophic and are mostly holozoic in their nutrition. These also pass through certain larval stages during their development.

Classification Of Animal Kingdom For NEET Criteria Of Classification

Habitat Mode of living and orientation of the body

• Aquatic. Those animals which live in water.
• Marine. Those animals which live in seawater.
• Freshwater. Those live in waters other than sea water Exampleponds, drains, ditches, lakes, rivers, slow or fast running streams, etc.
• Amphibious. Those animals which can live on land as well as in water, Examplefrog.
• Terrestrial. Those that live on land Exampleman, lizards, etc.
• Aerial. Those animals which can live in the air, Examplebirds and bats.
• Zooplanktons. These float on the water’s surface and are drifted by water currents Example small crustaceans like Daphnia, Cyclops, etc.
• Nektons. These swim actively in a sea or a lake Examplemost of fishes. Zooplanktons and the nektons which live in open waters, are collectively called pelagic animals.
• Benthos. These live on the bottom of water bodies Examples, are corals, echinoderms, etc.
• Out of these, sponges and corals are fixed to the substratum and are called sedentary or sessile animals.
• Neustons are animals floating or swimming in surface waters. Neritic are the animals found in coastal waters.
• Terrestrial animals. These animals live on land. They are again of the following types:
• Scansorial animals. These climb the walls, rocks, etc. Examples are lizards, flying squirrels, etc.
• Aerial animals. These can go in the air Examplemost for insects and birds, bats, etc.
• Cursorial animals. These are fast-runners Examplehorse, rabbits, lions etc.
• Pelagic. Living in the surface water of the sea.
• Arboreal. Those animals which live on trees and catch hold of tree branches Examplemonkeys.
• Burrowing (Fossorial). Those animals that form burrows in the sand or soil, for example – earthworms, snakes, some fishes, etc.
• Cave dwelling. Those which live in caves, for example- Lions and some fishes.
• Solitary. Those animals that live alone or single individually Exampleman, cats, dogs, etc.
• Colonial. Those which form colonies to live together, for example- Bees, ants, some coelenterates, (Physalia, Obelia), porifers (Sycon), etc Sedentary. These are fixed animals attached to substratum Example sponges, obelia, and
  most coelenterates.
• Free swimming. They swim actively in water. Sessile. These animals do not possess stalk. Sub-sessile. They possess stalk.
• Orientation of body
• Oval shaped. The shape of the body is like an egg.
• Cylindrical. The shape of the body is long and spherical, resembling a cylinder.
• Elongated. The body is long.
• Oblong. The body is oval and long (oval + long)
• Depressed body Dorsoventrally flattened body.
• Laterally compressed. Pressed laterally.
• Abond. Located away from, or on the opposite side of the mouth.
• Adoral. Located on the same side of the body surface as the mouth.

Body Segmentation

• Metamerically segmented body. A linear repetition of body parts is known as a segmentation (metamerism) example. Pheretima.
• Somite. Each repeated unit is somite.
• Appendages. Body pints protrude from the main body and serve in locomotion, feeding, mating, etc.

Skeleton

• Exoskeleton. Skeleton, which lies outside the body, for example- scales, feathers, nails, hairs, etc. It protects the body.
• Endoskeleton. Skeleton which lies inside the body, supports and protects internal organs, composed of cartilage or bone.

Detailed Notes On Non-Chordates Classification For NEET

Formation of mouth

• Protostonies. In most of the phyla (Platyhelmithes, Annelida. Arthropoda, Mollusca, and smaller groups), a tired mouth is formed in front of the blastopore of the embryo. These are called protostomes.
• Deuterostomes. In echinoderms, hemichordates, and chordates, the mouth arises remote front of the blastopore, and the latter becomes the anus.

Mode of running

Unguligrade

• Running on the tips of digits Example Horse, Rhinoceros, Ass, Zebra, Giraffe, etc.
• Plantigrade Walking on the palm of sole
• Digitigrade—Walking on toes Example Cat, Dog.

Level of organization

• Cellular organization. The animal body is formed of many cells but the cells show no coordination to form tissues Example sponges.
• Tissue organization. The animal body is formed of many cells that coordinate for the specific function and form four types of tissues Example epithelial tissue, connective tissue, muscular tissue, and nervous tissue Example coelenterates like Hydra.
• Organ-system organisation. The body is multicellular and cells coordinate to form tissues, organs, and systems Examples from flatworms to mammals.

Symmetry

Asymmetry- When the animal cannot be cut into two halves Example Amoeba. Radial or Biradial Symmetry. The radially symmetrical animals are mostly spherical or cylindrical. These can be cut into two halves, if we cut them through any radius of the animal, for example, most of the coelenterates and all the echinoderms.

Radial symmetry is again of the following types:

1. Tetramerous Radial symmetry. When in radial symmetry, the body parts are arranged in fours or multiples of four Example Jellyfish.
2. Pentamerous Radial symmetry. When in radial symmetry, the body parts are arranged in five or multiples of five Example echinoderms.
3. Hexamerous Radial symmetry. When in radial symmetry, the body parts are arranged in sixes or multiples of six Example Sea anemone. In sea anemones, the body can be divided into two similar parts only by one or two vertical planes and have biradial symmetry.
4. Bilateral symmetry. When the animal can be cut into two exactly equal and similar halves by one plane only Example Platyhelminthes to Chaetognatha and also vertebrates.

Sides in a Bilaterally Symmetrical Animal.

• Anterior side. It is that side of the body which is kept forward during locomotion.
• Posterior side. It is that side of the body that is opposite to the anterior side of the body.
• Dorsal side. It is the upper side of the body which is away from the substratum during locomotion.
• Ventral side. (L. Venter = belly). It is the lower side of the body which is towards the substratum during locomotion.
• Lateral sides. The right and left sides of the body are called lateral sides.

Body cavity

• Coelom. The body cavity is bounded externally by the parietal layer of the peritoneum and internally by the visceral layer of the peritoneum.
• Coelomate (Eucoelomate). The animals that possess true coelom. (True coelom is a cavity between the body wall and visceral organs and must be formed from mesoderm) Example Bryozoa.

Based on origin, coelom is of two types :

• Schizocoel. When coelom is formed by splitting of mesoderm Example annelids, arthropods, and mollusks. The animals having schizocoelic coelom are grouped in Schizocoela.
• Enterocoel. When coelom is formed from the enteron ofgastrula Example echinoderms and chordates. Such animals are grouped in Enterocoela. Acoelomate. These organisms lack coelom. They include all members up to phylum Platyhelminthes.
• Pseudocoelomata Animals in which false coelom is present. Body cavity, if present, develops from blastocoel, for example- Rotifera, Nematoda. Haemocoelomatas.
• In Arthropods and mollusks, the true coelom is reduced and the body cavity is filled with blood and is called hemocoel, and animals are termed haemocoelomates.

Modes of Respiration

Modes of excretion

• Ammonotclism. When the main nitrogenous waste is NH3 the animals excreting ammonia are called ammonotelic animals. The water loss from the body along with ammonia is 300-900 ml/gm of NH3. It is found in aquatic animals Example Protozoans, sponges, coelenterates, crustaceans, echinoderms, and bony fishes.
• Ureotelism. The main nitrogenous waste is urea and the animals possessing it are called ureotelic animals. The loss of water along with urea is comparatively less. It is 50ml/ gm of urea. It is found in amphibians, mammals, and cartilage fishes.
• Uricotelism. The main nitrogenous waste is uric acid and animals possessing it are called uricotelic animals. Water loss is quite less and is just lOml/gm of uric acid. It is expelled as a semisolid paste. It is found in reptiles, birds, and insects.
• Mollusks like Limnaea, Unio, etc. are amniotic (expel amino acids) while certain bony fishes (especially teleosts) have trimethylamine as nitrogenous waste.

Cold-blooded or warm-blooded

1. Homeothermal or Endothermic (Warm-blooded animals).
2. In this, body temperature Is constant and does not change with the change in environmental temperature Example birds and mammals.
3. Homeothermal Or endothermic (Cold-blooded animals). In this, body temperature is not constant and changes with changes in environmental temperature.

These defend themselves in two ways:

1. Hibernation (Winter-sleep). In this, animals hide themselves in winter months and become inactive Example amphibians (frog; and lizards.
2. Aestivation (Summer-sleep). In this, animals hide in shady areas during hot summer months. amphibians.

Detailed Notes On Non-Chordates Classification For NEET

Blood Vascular System

1. Open type circulation Example Arthropods, mollusks.
2. Closed type circulation Example. Annelids and most of chordates.

Body Plan

1. Cell aggregate
2. Blind sac and
3. Tube in a tube body plan

Number of germ layers

• Diploblastic animals. In sponges and coelenterates, gastrula has two layers, outer ectoderm, and inner endoderm, so they are called diploblastic animals, for example, Porifers and coelenterates.
• Triploblastic animals. From flatworms to mammals, gastrula larva has three germ layers, outer ectoderm, middle mesoderm, and inner endoderm. So these are called triploblastic animals, for Example Platyhelminthes onward all phyla.

Reproduction

• Monoecious.When one individual of a species possesses both the male and female reproductive organs Example Pheretima, Taenia, Fasciola, etc. Hermaphrodite. It is a synonym or duplicate name of monoecious.
• Dioecious. When male and female reproductive organs are borne by separate individuals, the situation is called dioecious, for example- Man, Pila, Prawn, etc.
• Sexual dimorphism. If we can distinguish male and female individuals of a species by looking at their external features only, the phenomenon is called sexual dimorphism. Or, Males and females possess different shapes.
• PoIymorphism.The occurrence of at least tv/o, usually several, radically different body forms within colonial or social organisms.
• In unisexual animals, sperms and ova are derived from different animals, called cross-fertilization, In some bisexual animals, sperm and ovum of some animals fuse, called self-fertilization Example in Taenia.
• But in some bisexual animals, cross-fertilization occurs due to conditions: protandrous and protogynous. In protandrous conditions (Proto = first, android = male), testes mature earlier than ovaries Example leech, earthworm, etc.

In protogynous conditions (Proto =first, gynae = female), ovaries mature earlier than testes Example Scypha, and Herdmania (Sea squirt).

• Polygamy. When one male lives in the company of many females Example Struthio.
• Holoblastic Cleavage. The cleavage of the egg is complete; for example—in many invertebrates, amphioxus, amphibians, and mammals.
• Meroblastic Cleavage. The egg divides incompletely due to too much yolk in it The cleavage is confined to a limited portion of the egg, for example, Squids, insects, many fishes, reptiles, and birds.
• Metamorphosis. The larva undergoes certain changes to become adult, this process is called metamorphosis.
• Progressive Metamorphosis. When the larva is simple and becomes complex in the adult stage, for example- the Tadpole of a frog changes into an adult. Retrogressive Metamorphosis. When the larva is complex and more advanced than the adult.
• It loses its certain characters, for example –
• Ascidians. The larva has a well-developed notochord and nerve cord while these structures are absent and reduced respectively in adults.
  • Monogenetic life cycle. When a parasite completes its life cycle in a single host Example Ascaris.
  • Digenetic Life cycle. When a parasite completes its life cycle in two hosts.
  • Pheromones. Secretions of glands are released in the air. These generally act as sex attractants.
  • Autotomy. The ability of self-amputation.
  • Regeneration. Ability to make up lost parts.

Classification Of Animal Kingdom For NEET Phylum Porifera

Unique features

• The canal system consists of pores, canals, and chambers facilitating the continuous flow of water for nourishment, respiration, excretion, and reproduction.
• Cellular organization within the body.
• Lack of oral cavity and gastrointestinal tract.
• Choanocytes, also known as collar cells, line the diverse passageways and spongocoel.
• Existence of spicules, spongin fibers, or both.
• The free-swimming larvae, termed parenchymula (Lcucosolenia & Clathrina) and amphiblastula (Sycon), function as a primary mode of dispersal for this predominantly sessile phylum.

Classification Of Animal Kingdom For NEET Cells Of Sponges

• Choanocytes (also known as “collar cells”) flagellated cells which function as the sponge’s digestive system, are remarkably similar to the protistan choanoflagellates.
• The collar is composed of microvilli and is used to filter particles out of the water.
• The beating of the flagella of choanocytes’ creates the water current that enters the spongocoel.

• Pinacocytes. Form the pinacoderm, the outer epidermal layer of cells. This is the closest approach to true tissue in sponges.
• Porocytes. Tubular cells make up the pores in the sponge body through the mesohyl.
• Myocytes. Modified pinealocytes control the size of die and pore openings and thus (lie water flow.
• Archaeocytes (or microcytes). They are totipotent cells that can transform into. They also have a role in nutrient transport and sexual reproduction.
• Sclcrocylcs. Secrete calcareous or siliceous spicules that reside in the mesohyal.
• SpoiRocyles. Secrete spongin, collagen-like fibers which make up the mesophyll.
• Collcncytcs. Secrete collagen.
• Spicules. Stiffened rods or spikes made of calcium carbonate or silica are used for defense.
• Sensory anil nerve cells are absent in sponges.
• Spongioblasts. Spongin-fibre-secreting cells of sponges.
• Out of these, myocytes are derived from the dermal layer, while other amoebocytes are derived from the gastral layer.
• Cells are arranged in a gelatinous non-cellular matrix called mesohyal.

Position of Chomocytes

• Line the spongocoel in the Ascoiioid canal system.
• Line the radial canals in the Syconoid canal system.
• Line the flagellated chambers in the Lcticoitoid canal system.
• In the cavity of Eupleclella, a pair of crustaceans- Venusta spongicola lives till death.
• Prosopylc: An aperture between the incurrent and radial canal of Scypha.
• Apopyle: An aperture between a radial canal and an excurrent canal of Scypha.
• Geniniulation: Formation external buds in sponges.
• Gentmule: An internal bud of Spongilla. II is formed by a coat of spicules. It helps in perennation. Spicules- kinds.
  1. Rod-like or (long, short spear or club-like (excites)
  2. Three-rayed or Triradiate
  3. Tetaradiate
  4. Six rayed.
• Chemical nature.
• Calcareous or siliceous
• Costliest bath sponge – Spongia officinalis (natural sponge)
• Spongilla colony. Green in color.
• Gemmules are endogenous buds of sapodilla and help in asexual reproduction
• Euspongia. brown
• Spongia and Hippospongia provide bath sponges of commercial value
• The largest sponges belong to the class Demospongiae. A tropical logger-head sponge (Spheciospongia) forms a mass of over a meter in height and diameter
• Sponges are the lowest metazoans and arc placed in sub-kingdom Parazoa.
• Parazoology. Scientific study of sponges.
• Robert Grant. Coined the term Porifera.
• Ellis: Recognised the sponges as animals.
• The dermal ostia of sponges are analogous to mouths, while the osculum is analogous to the anus.
• The Mesogloea of the sponge is known as mesohyal or mesenchyme.
• Spongilla is a common and widely distributed freshwater sponge,
• Ieucosolenia is one of the simplest sponges.

Reproduction in sponges

Asexual reproduction

• By budding External/Exogcnous In budding, numerous archaeocytes collect at the surface and the placoderm bulges out to receive them. The bud so formed grows in an adult individual, ft either remains attached to the parent individual or gets detached and attached nearby to develop into an independent colony.
• Formation of gemmules (Internal/endogenous buds) All freshwater and some marine sponges (Ficulina, Tethya, Suherites, etc.) have a regular and peculiar mode of asexual reproduction by internal buds, called gemmules (Gr., gemma, bud).
• These eventually detach and develop into new individuals. Gemmules enable the sponges to tide over unfavorable conditions, such as excessive cold or draught, because they can withstand freezing and considerably greater degrees of desiccation than adult sponges.
• Fission-In some sponges, multiplication takes place by fission, throwing off parts of the body. The sponge is hypertrophied over a limited area, developing a line of weakness.
• Along this weak line, splitting occurs and a part is separated from the main parental body which develops into a new individual. By budding, this new individual takes the form of a colony.
• Formation of reduction bodies Another very unusual method of asexual reproduction is the formation of reduction bodies. Most freshwater and marine sponges disintegrate in adverse circumstances.
• The ailing sponge will usually collapse leaving small rounded balls, called reduction bodies.
• Each body consists of an internal mass of amoebocytes, covered externally by a pinacoderm. When favorable conditions return, these reduction bodies grow into completely new sponges.

Classification Of Animal Kingdom Non Chordates NEET Notes

Sexual Reproduction

• Sperms and ovum arc are derived from archaeocytes or choanocytes which undergo gametogenesis.
• Sperms are released outside through outflowing water and make their way into another sponge along with the ingressing water.
• Sperms arc carried by sperm-transit cells to the ovum.
• Fertilization is internal.
• The development includes amphiblastula or parencliymula larva.
• Amphiblastula is a hollow, oval larval stage, characteristic of many calcareous sponges (Example Scypha). Anterior one-half of amphiblastula bears flagella, whereas the posterior half does not.
• The parenchymula is a solid, oval, or flattened larval stage. It is characteristic of some calcareous, hexactinellid, and most demosopongians. The entire outer surface bears flagella.
• With the help of external flagella, the motile larvae escape from the parental body and swim for a few hours to many days. Finally, they settle down, become attached to some solid object, metamorphose, and grow into adults.

Classification Of Animal Kingdom For NEET Phylum-Coelenterata—(Cnidaria)

Unique features

1. Tissue level of organization.
2. Special kinds of stinging cells or cnidoblasts are meant for offense, defense, and food catching.
3. Diploblastic, radially symmetrical, and mostly show polymorphism.
4. The epidermis surrounds the cnidarian’s ‘stomach’ or gastrovascular cavity which functions as both mouth and anus. It is used both to ingest food and excrete waste.
5. It also serves along with the mesogloea as a hydrostatic supporting skeleton. Firm skeletons are only found among polyps, which produce lime for that purpose.
6. The gastrovascular system plays a role in the digestion and dispersion of food and the removal of metabolic waste.
7. It surrounds the gastrovascular cavity as well as its extension in the tentacles of polyps. Thus the gastrovascular system serves two separate functions, digestion, and transport.
8. Digestion is both intracellular and intercellular or extracellular.

Classification Of Animal Kingdom For NEET Kinds Of Nematocysts

• Penetrants or Stenoteles. They are the largest.
• Volvent or desmosomes. They are the smallest, used only for obtaining food.
• Small glutinanLs or Alrichous or his, Butt absent and help in fixing loan object.
• Large glulinants or Ifolotrichous isorhiza. The long thread is open at the free end. They slick to an object.

Classification Of Animal Kingdom For NEET Hydra

Features of Hydra

• It is a fixed animal and is found attached to submerged weeds and stones. Though it is fixed, it can move about when required. If disturbed, it contracts to a small spherical or oval mass.
• It is carnivorous as its food consists of small crustaceans and larvae of insects.
• Digestion is intercellular as well as intracellular.
• Hydra has a slender tubular body and exhibits distinct radial symmetry. The body is extremely contractile and length varies from 10 to 30 mm.
• The lower end of the tubular body is closed and this side is designated as the aboral or proximal end. This side of the body is named a foot or basal disc.
• It is used as a structure for attachment to the substratum and it helps in locomotion.
• The opposite end (the distal or oral end) is free and possesses the opening of the mouth, situated at the summit of a conical elevation called the hypostome or manubrium.
• The manubrium is usually surrounded by several tentacles. The tentacles are fine hollow processes and help in catching food.
• The mouth leads into the coelenteron which occupies the interior of the body. It is continuous with the cavities of the tentacles.
• The epidermis and Gastrodermis are the two cellular layers of the body wall of Hydra. In between these two layers is also present a non-cellular jelly-like mesogloea.
• The epidermis is the outer protective layer and cellular. It forms nearly one-third of the thickness of the body wall. It consists of the following types of cells:
  • Epitheliomuscular cells or
  • Musculoepithelial cells
  • Interstitial cells
  • Cnidoblasts or Nematoblasts
  • Nerve cells
  • Sensory or receptor cells
  • Germ cells.
• Nematocysts are of 4 types i.e. Penetrant (Stenotele), Volvcnt (Desmoneme), Glutinant streptoline (Holotrichous isorhiza), and Glutinant steroline (Atrichous isorhiza).
• Gastrodermis. It forms nearly two-thirds of the thickness of the body wall. It is always found forming the lining of the gastrovascular cavity. It consists of five types of cells:
  • The nutritive muscular cells
  • The secretory cells
  • The sensory cells
  • The nerve cells
  • The interstitial cells.

Classification Of Animal Kingdom For NEET Useful Information

• Leukart Gave the term coelenterata.
• Peyssonel (1723): Reported the animal nature of coelenterates.
• Coelenterates are commonly called cnidarians due to the presence of cnidoblasts, so the study of coelenterates is called cnidology.
• Coelenterata name is due to the presence of the coelenteron cavity.
• Obelia is a trimorphic and marine colony.
• Planula larva is formed during the life cycle of Obelia.
• Coelenteron is present which is known as a gastrovascular cavity.
• Cell differentiation and Physiological division of labor are distinct in Hydra.
• Digestion is extracellular as well as intracellular.
• Respiratory organs, Blood, vascular system, and excretory organs are absent.
• The epidermis and Gastrodermis are cellular layers and are separated by mesogloea.
• Mesogloea is the non-cellular layer that is secreted by the epidermis and gastrodermis.
• Obelia and Aurelia show an alternation of generation and phenomenon of metagenesis.
• The main stem of Obelia is called the stolon which gives rise to hydrorhiza which is attached to a substratum.
• Most probably Triclwplax represents the most primitive living metazoans.
• Totipotent interstitial cells are the characteristic of Hydra.
• When development starts, obelia is a monomorphic form having polyp only but later due to the development of blastostyle it becomes a dimorphic colony and finally medusae but over the blastostyle in a mature colony, then it becomes a trimorphic colony.
• Some coelenterates can paralyze people swimming in the seas. ‘Sea wasp’ a coelenterate is one of the most poisonous animals.

Metagenesis. In the life cycle of Obelia, there is regular alternation between fixed polypoid and free swimming medusoid phases, both of which are diploid. Such an alternation between two phases is called metagenesis.

In metagenesis, the adult polyp forms male or female medusae (diploid) asexually.

There are three principal asexual events:

• Budding Strobilation occurs when a medusa forms on the higher (oral) end of the polyp, and is common among scyphozoa finally, complete metamorphosis, from polyp to medusa form can also occur.
• Some coelenterates that show polymorphism are Obelia, Physalia, and Velella. Physalia shows excessive polymorphism having gastrozooids, dactylozooids, and gonozooids.
• In India, medusae of Aurelia are commonly found in coastal waters of Madras.
• In the development of Aurelia (a jellyfish), both planula (larva) and ephyra (larva) are present.
• Obelia. Seafur, a marine, sedentary, and trimorphic colonial coelenterate.
• It has 3 types of zooids: nutritive and flower-like polyp enclosed in a hydrotheca; long and cylindrical mouthless blastostyle enclosed in a gonotheca; and umbrella-like dust with gonads and developed as a bud on the blastostyle. It is commonly called zoophyte due to its plant-like appearance.
• Corals are skeletons secreting anthozoans, while sea anemones are anthozoans with skeletons.
• Coral reefs. A coral reef is a ridge in the sea and is formed of skeletons of the coelenterates called corals. It is mainly formed of skeletons of stony corals like Madrepora but is impregnated by skeletons of Millipore and Tubipora.

It is mainly formed of calcium carbonate. These are of 3 types (by Hyman, 1940):

• Fringing reefs. These extend from the shore up a distance of 400 meters into the sea.
• Barrier reefs. These run parallel to the shore but are separated from slower by a water body called a lagoon. The largest barrier reef Great Barrier Reef in the north-east coast of Australia and is 1920 km long.
• Atoll. It is circular coral surrounding a quiet water body called a lagoon. It is also called Coral Island.
• In India, Lakshadweep islands are formed of coral reefs.
• These are mainly found in warm (70°F) and shallow waters of tropical seas. The Pacific northeast of Australia is called the Coral Sea.
• Corallite is the skeleton of an individual coral, while coenosteum is the colonial skeleton and is called corallum when it is branched.
• Corallium rubrum. Also called red coral (moonga), while Meandrine is commonly called brain coral.
• Rhizostoma. A polytomous scyphozoan with many mouth-bearing structures called scapulets.
• Aurelia. Three larval stages in the life cycle: Planula (ciliated for dispersal), Scliyphistoma (represents reduced polypoid stage and forms ephyrae by transverse fission called strobilation), and ephyrae.

Important Non-Chordates NEET Questions With Answers

Classification Of Animal Kingdom For NEET Phylum—Acnidaria Or Ctenophora

• Phylum Ctenophora was established by Hatschek (1839).
• Phylum Ctenophora is also called Aaiidaria as these lack cnidoblasts.
• Gastrodes parasiticum is only an endoparasitic ctenophore.
• Mesogloea ofctenoplwres is of collenchyma nature (with many cells).
• Ctenophora is a small phylum of marine coelenterates like free swimming and biradially symmetrical animals having 8 meridional rows of ciliary comb ribs.
• They are popularly called comb jellies, sea combs, and sea gooseberries.
• Cnidoblast are absent except Eucldora rubra.
• They possess phagocytes or light-producing structures, therefore are luminescent.
• Tentacles, when present, are solid and possess adhesive cells called colloblasts (= lasso cells).
• Ctenophores are acoelomates.
• The body plan is intermediate between the blind sac and tube within the tube.
• Animals are usually monoecious. An immature ciliated stage larva called cydippid larva is found in some forms.
• Ctenophoria has two classes- denticulate (with tentacles), Example Hormiphora, and nuda (without tentacles), Example Beroe.

Classification Of Animal Kingdom For NEET Phylum- Platyheminthes

General Characters of Phylum Platylielmintlies

• Body form. Body dorsoventrally flat, unsegmented leaf or ribbon-like.
• Germ layers. Triploblastie animals, with three germ layers ectoderm, endoderm, and mesoderm.
• Habitat. Mostly parasites with some five living forms.
• Symmetry. Bilaterally symmetrical.
• Level of Organisation. Body organization is at the level of organ and organ-system grade.
• In parasites, forms suckers and hooks are present lor attachment to host tissues.
• Body cavity. True body cavity absent i.c. acclimate.
• Incomplete alimentary canal present. In the alimentary canal, the mouth is present but the anus is not present. In some endoparasites alimentary canal is absent.
• Respiration is aerobic in free-living forms and anaerobic in endoparasites.
• Excretion is mainly ammonotelic. For excretion special cells called flame cells or protonephridia are present.
• Nervous system. Due to capitalization, a nerve ring is present.
• Sense organs. Photoreceptors are present in free-swimming forms.
• Reproduction. The reproductive system is highly developed and bisexual. It is an adaptation of a parasitic mode of life.
• The life cycle is usually complicated. It is again an adaptation to a parasitic mode of life

Classification Of Animal Kingdom For NEET Parasitism

It is an association between different species in which one is benefited and the other is harmed. The organism which is benefited is called a parasite and the other that suffers is termed a host. It is interesting to note that hosts can live without parasites but parasites cannot survive without hosts.

Types of parasites

1. Temporary or partial parasites. These are animals that spend a brief period of their life as parasites and a major part as free-living forms.
   1. Examples: The Glochiditim larva of freshwater mussel is ectoparasitic on fishes for a short period, whereas the adult mussel is free living.
   2. Hymenoptera larvae are parasitic on caterpillars, whereas the adults are free-living.
2. Permanent parasites. They are parasites throughout their life.
3. Ectoparasite (External Parasite). They live on the surface Example Diplozoon indicum parasites on the gill of freshwater fishes.
4. Endoparasites. Many live inside the host’s body Example Taenia in the intestine, Paragonitim in the lungs, Polystomium in the urinary bladder Fasciola hepatica in the liver, and Schistosoma in the blood. They live in the host body, within the cells. (Cytozoic), tissue (histozoic) or cavities (coelozoic).
5. Monogenetic parasites (life cycle). Life history completed in a single host. Example Polystomum and Diplozoon.
6. Non-pathogenic parasites. They do not cause any diseased conditions in the host body.
7. Digenetic parasites. These parasites require two hosts to complete their life cycle.
8. The host in which the parasite grows into its adult phase is called final, definitive, or primary while the one that simply serves to transmit the parasite from one definitive host to the other is called intermediate, secondary, or vector host.
9. Accidental parasites. These are swallowed accidentally.

Examples: Soil and freshwater nematodes.

1. Mode of infection of helminth parasite
2. Swallowing of contaminated food.
3. Boring through skin Example Schistosoma.
4. Direct contact Example Diplozoon.

Adaptations of helminth parasite

Morphological Adaptation

1. Loss of organs. Locomotory organs, digestive organs, sense organs.
2. Continuation of pre-existing features. Thin flat body, shelled egg.
3. Development of new structure. Adhesive organs tegument, sucking pharynx, cyst wall around infective larvae.

Non-Chordates Classification NEET Previous Year

Physiological adaptations

1. Anaerobic respiration.
2. Secretion of anti-enzymes and mucus.
3. Evasion of the host’s immune system.
4. Chemotoxin
5. Excessive multiplication

Classification Of Animal Kingdom For NEET Fasciola Hepatica (Liver Fluke)

• Liver fluke lives as endoparasite in the bile ducts and canaliculi within the liver and remains attached by an oral and a ventral sucker (acetabulum).
• Upto 200 flukes may be present within a sheep. The mouth is situated in the oral sucker. No anus. Liver fluke is hermaphrodite (monoecious) but cross-fertilization takes place.
• There are two tests. Ovaries and vitelline glands are separate. Laurer’s canal is the temporary opening that receives the cirrus of the male during copulation.
• After fertilization eggs are laid in the bile ducts from where through the intestine they come out with the feces. The shell gland secretes the secretion which hardens to form the shell (capsule). Further development takes place in humidity.

Life Cycle of liver fluke

• The life cycle is digenetic, the primary host is sheep and the secondary host is a snail.
• Eggs enclosed in capsules develop into miracidium larva which hatches in water and enters into the body of a snail (in digestive glands).
• Miracidium will die if it does not reach a suitable host within 24 hours of hatching.
• It develops into sporocyst larvae which form at least two aerations of 5 to 8 media larvae.
• Each media larva forms 14 to 20 cercaria larvae by its ns cells. Cerearia larvae come out of the body of the snail and swim with their tail.
• After some time they get attached to leaves of water vegetation and become encysted to the next larva i.e. metacercaria.
• When sheep feed on aquatic vegetation, metacercaria reaches the alimentary’ canal, where the cyst is dissolved by digestive enzymes and cercaria reaches the liver through the bile duct and develops into adult flukes.
• It causes fascioliasis or liver rot, anemia, and excessive edema of the jaws. Heterogamv.
• A kind of alternation of generations in liver fluke, in which there are alternations between sexual phase represented by adult worms and parthenogenetic generations represented by media and cercariae larvae. Polyembryony.
• In Liver fluke, the germ cells present in larval form are not eggs but they are diploid cells derived by mitotic divisions from propagatory cells separated from zygote. Thus zygote produces many larvae. It is termed as polyembryony.

Classification Of Animal Kingdom For NEET Schistosoma Haematobium

Blood fluke

Commonly known as a blood fluke. It is a digenetic parasite, the primary host is man and the secondary host is Limnea (snail). It causes schistosomiasis or Bilharziasis. Males and females are separate. Females live in the gynaecophoral canal of males.

Classification Of Animal Kingdom For NEET Taenia Solium (Tapeworm)

1. This lives as an endoparasite in the digestive tract where it is anchored to its mucosa by its scolex and absorbs the host’s digested food.
2. It is found in all those parts where the pig is domesticated.

1. Its body is opaque, flat, long, and ribbon-like, measuring 2.8 meters on average.
2. The body is divided into Head (Scolcx), the unsegmented neck, and the segmented strobiln.
3. The head has 4 muscularsuckers and two rows of hooks around the rostellum. The hooks and suckers are meant for attachment. The strobila has about 800-900 segments known as probiotics. These proglottids at the posterior end are sexually mature and known as grnvids.
4. The gravids break off from the body and pass out with feces. This loss of gravity is made good by the neck which makes new proglottids.
5. The body walls consist of a cuticle that rests on the body musculature that binds mesenchyme.
6. Respiration is mainly anaerobic or anoxybiotic.
7. The excretory system consists of lateral longitudinal canals, secondary canals, capillaries, and flame cells.
8. Tapeworm is bisexual (hermaphrodite). Each proglottid has a large number of testes and a single bilobed ovary. Fertilization is internal and the zygotes are stored in a very much-branched uterus. There may be upto 30,000 zygotes present in the items of one gravid. The zygotes are covered with a thick layer of shell.
9. Life Cycle. The gravids break off (apolysis) from the body and pass out with feces.
10. If these feces are eaten by a pig, the zygotes reach into the alimentary canal of the pig. Each zygote produces an embryo with 6 hooks known as a Hexacanth embryo.
11. The hexacanth embryo along with the shell is known as the oncosphere. The shell gets dissolved in the intestine of the pig, the hexacanths come out.
12. These hexacanths pierce the wall of the intestine and enter into the bloodstream. The hooks disappear and each hexacanth embryo changes into a bladder-like structure known as a bladder worm (Cysticercus larva).
13. These larvae now settle into the voluntary muscles of pigs. If a man eats such a pork which is highly infested with bladder worms, they reach into the intestine of the man and one of the bladder worms develops into a Taenia.
14. Parasitic adaptation. Locomotory organs and digestive system absent Hooks and suckers present for attachment to host’s intestine Cuticle permeable for absorption of digested food from host’s intestine, Produces some anti enzymes which neutralize the enzymes and Taenia does not get digested itself, The osmotic pressure of the body fluids of Taenia is the same as that of man.
15. Because there is one Taenia found in the intestine of one person hence it is bisexual, It produces a very large number of ova because there is a lot of wastage of ova in the feces, and Sense organs are very much reduced.

Classification Of Animal Kingdom For NEET Taenia Saginatathe, Beef Tapeworm

Taenia saginata is comparatively longer than Taenia solium and the scolex does not have rostellum and hooks. It has 4 muscularsuckers only. There may be upto 2000 proglottids present in the body. The intermediate hosts are cows and buffaloes. It causes Taeniasis and cycticercosis.

Classification Of Animal Kingdom For NEET Important Information

Turbellarians (Planarians).

• Dugesia is with a triangular head with two auricles, while Planaria is with a truncated head.
• The pharynx is protrusible through the mouth.
• Rhabditis: Rod-like bodies in the epidermal cells. Their secretion is probably protective and adhesive in function.
• The Planarian eye is an inverse eye in which light has to pass through the photoreceptors and then fall on pigment cells.
• Bipalium: Only terrestrial planarian.
• Morpholactic regeneration. One part of the body can form the whole body.
• Neoblasts: Cells of planarians that help in regeneration.

Trematodes (Flukes).

• Schistosoma (Blood-fluke). It is the only unisexual fluke found in the veins of man. Female is present in the gynaecophoral canal (a groove on the ventral side) of males. It causes schistosomiasis characterized by intestinal disorders. It is also called Bilharzia.
• Opisthorcliis sinensis. Chinese liver fluke of man.
• Paragonimus. Lung fluke of man.

Animal Kingdom Non-Chordates NEET Topic Wise Study Guide

Fasciolopsis buski: Intestinal fluke of man.

• Monogenetic flukes. With a monogenetic life cycle, for Example Diplozoon (ectoparasite of gills of fishes), Gyrodactylus.
• Digenetic flukes. With two hosts in the life cycle Example Fasciola, Schistosoma, etc.
• Prohaptor. Anterior sucker of flukes.
• Opisthaptor. Posterior sucker of flukes.
• Amphistomous flukes. Fluke with 2suckers, one at each end of the body Example Paramphistomum.
• Fasciola is with two testesand one ovary. Miraridium and cercaria are in free-swimming stages, while sporocyst and redia are inside the snail.

Cestodes (Tapeworms)

• Taenia saginata (Beef-tapeworm). It is found in the small intestine of man. The secondary host is a cow. Human infection is by taking undercooked measly beef. Its scolex is without hooks and rostellum while strobila is formed of about 2,000 proglottids.
• Taenia has a bilobed ovary and about 200 follicular testes.
• The world population suffers more from Taenia saginata than T. solium due to more beef eaters.
• Bothria: Longitudinal groove-like adhesive organs of tapeworms.
• Suckers. Cup-like adhesive organs.
• Onchosphere. Encapsulated larvae are found in the uterus of gravid proglottids.
• Apolysis. Loss of gravid proglottids from the posterior end of the body.
• Strobilation. Formation of new proglottids from the neck, also called
  pseudometamerism.
• Echinococcus. Hydatid worm. Its hydatid cyst shows exogenous as well as endogenous budding. Parasite of small intestine of dogs, cats, etc. It has only 3-4 proglottids.
• Diphyllobothrium. Largest tapeworm (18 m).
• Hymemolepis. Dwarf tapeworm (2-4.5 cm). It is a monogenetic tapeworm of man.
• Dipylidum. Dog tapeworm.
• Scolex is the adhesive part of tapeworms.

Classification Of Animal Kingdom For NEET Phylum Aschelminthes

General characters of Phylum Ascheliminthes

• Body form. Cylindrical body but circular, in outline in cross-section.
• Germ layers Triploblastic animals with three germ layers.
• Habitat, Some are free living and many are ectoparasites and endoporasites of animals as well as plants.
• Level of organization. Body organization is at the level of an organ system.
• Symmetry. Bilaterally asymmetrical.
• The body is covered with thick, tough, and spiny cuticles.
• The epidermis is syncytial.
• In the body fixed number of cells are present.
• The alimentary canal is complete and straight.
• Circulatory system absent.
• Respiratory system absent.
• Respiration is aerobic in free-living forms and anaerobic in parasitic forms.
• Special types of sense organs known as phasmids are present.
• The nervous system is well developed with a nerve ring, ganglia, and nerve cords.
• The excretory system is simple, formed of specially shaped cells.
• Excretion is ureotelic.
• Reproduction. Sexes are separate with a well-developed reproductive system.
• Shows sexual dimorphism. Usually, females are longer than males.

Detailed Notes On Non-Chordates Classification For NEET

Classification of Phylum Aschelminthes.

• Class Nematoda (Sub-class Phasmida).
• Phasmid present, pouch-like sense organs and act as chemoreceptors present] Dracunculus medinensis (guinea worm), Rhabditis.
• Sub-class Aphasmida. Phasmids absent Example Trilobius, Trichinella (Trichinia worms) Trichuris (whipworm)
• Class 2. Nematophora e.g, Paragordius,
• Class 3. Rotifera Example, Philondina, Rotaria.
• Class 4. Kinorhyncha Example Echinoderes.
• Class 5. Gastrotricha Example Chaetonotus, Macrodasys.
• Class 6. Pripaulida
• Class 7. Acanthocephala

(These classes are now treated as separate phyla)

Classification Of Animal Kingdom For NEET Ascaris Lumbricoides (The Round Worm)

• This is the common roundworm found as a parasite in the intestine of man and also in pigs, cattle, sheep, and squirrels.
• Sexes are separate and show sexual dimorphism. The male is comparatively smaller than the female. The male measures 15 to 30 cm long with the posterior end curved, whereas the female measures 20 to 40 cm long and straight. Cloacal aperture is present in males whereas in females separate anus and vulva are present.
• There are 4 distinct lines present on the body of Ascaris in the form of folds known as Epidermal cords. (Dorsal, Ventral, and two lateral cords).
• The mouth is situated at the anterior end surrounded by 3 lips known as Dorsal Lip and 2 Ventro-lateral lips. The lateral papilla and amphid are present on each ventrolateral lip.
• Amphid is the chemo and olfactory receptor.
• Excretory pores are present above 2 mm away from the anterior end.
• The body wall consists of a cuticle (non-cellular), syncytial ectoderm, and longitudinal muscle.
• Highly vacuolated, fluid-filled pseudocolor present.
• The alimentary canal starts from the terminal mouth surrounded by 3 lips. The mouth opens into the pharynx which is bulb-shaped and lined by cuticles. From the pharynx begins the intestine which leads into the narrow rectum which opens outside through the anus.
• The alimentary canal of Ascaris is mainly concerned with absorption ofthe food rather than digestion.
• The excretory system is more or less H-shaped. Two longitudinal excretory canals are joined by a transverse canal.
• Male reproductive organs consist of a single long and coiled thread-like testis that opens into the vas deferens of almost the same diameter.
• The vas deferens opens into a wide seminal vesicle. It leads into a narrow ejaculatory duct which opens outside through the cloaca. There are present a pair of pineal spicules which help during copulation.
• Female Reproductive Organs are didelphic i.e. double. There are a pair of thread-like ovaries. Each ovary continues into a slightly thicker tube known as the oviduct The two oviducts open into a broad and muscular utero. The two uteri join together and open into the vagina. The vagina opens outside through the female gonopore or vulva, which is situated on the ventral side about one-third of the length from the anterior end.
• Life History. The sperms of Ascaris are amoeboid which brings fertilization of eggs in the uterus.
• The fertilized eggs are covered with 3 layers. A female Ascaris lays about 15,000 to 200,000 zygotes each day in the small intestine of a man. These zygotes pass out with the human feces.
• The larvae are known as rhabdoid larvae or first stage juveniles which are formed within the zygotes.
• The first-stage juveniles still live within the eggshell and molt after 10 days to produce 2nd stage juveniles (infective stage about 0.2 to 0.3 mm long).
• After rupturing the shell, 2nd juveniles come out and wander in the body for 25 days, undergo second and third molting in the alveoli of the lungs, and by the time 4th stage juveniles are formed again and reach the alimentary canal where they grow into adults. In the intestine, they molt for the fourth time and grow into adults in about 2 to 3 months.

Classification Of Animal Kingdom For NEET Life Cycle Of Ascaris

Classification Of Animal Kingdom For NEET Wuchereria Bancrofcit

Human filarial worm

• It is predominantly located in tropical climates.
• Wuchereria is a dimorphic intercellular endoparasite of humans.
• Wuchereria inhabit the lymphatic arteries and lymph nodes of humans.
• Wuchereria bancrofti, sometimes referred to as Filaria bancrofti, induces elephantiasis disease (Filariasis).
• In filariasis, lymphatic tubes and glands become inflamed and clogged, resulting intissue enlargement due to the accumulation of lymphatic  fluid. Infection by Wuchereria (filaria) occurs via the Culex mosquito.
• The life cycle is digenetic in nature.
• Both male and female forms entwine with one another.
• Culex fatigans and Culex pipiens act as secondary hosts for Wuchereria.
• Female Wuchereria produce sheathed embryos known as microfilariae.
• Microfilariae are elongated, slender entities encased in a translucent sheath.
• Microfilariae enter the superficial blood circulation at midnight and are transmitted into the body of a mosquito (Culex) during the bite.
• Microfilaria transforms into sausage-shaped larvae within the thoracic musculature of mosquitoes.
• Microfilariae undergo two molts within the thoracic muscles of mosquitoes, transforming into elongated, slender forms.
• Long, slender microfilariae represent the infective stages that are subsequently transmitted within the primary host, namely humans.
• Significant pharmaceuticals include Antimony and Arsenic compounds, which eliminate both adult forms and microfilariae.
• The lifespan of Wuchereria is four to five years.

Ancylosloma (Hook worm)

• Ancylosloma is the worm of man.
• Ancylostoma is monogenetic.
• The Cloaca of the male is surrounded by a copulatory bursa. Hookworm causes Ancylostomiasis in which a person suffers from acute (severe) anemia.
• The free larval stage is found in the life cycle of hookworms.

Trichuris trichiura (whip worm). Endoparasite of caecum and large intestine of man. Heavy infection causes diarrhoea and anemia.

Rhabditis maupasi. A free living soil nematode.

Loa (Eye worm): Commonly found in subcutaneous tissue in Africans. These pass across the eyeball.

Enterobius (Oxyuris). Pinworm. An endoparasite of the large intestine of man. It is monogenetic. It causes enterobiasis characterized by sleeplessness, digestive and mental disorders, abdominal pain, etc.

Classification Of Animal Kingdom Non-Chordates NEET Notes

Trichinella (Trichina worm). An intestinal endoparasitic worm ofman. Reservoir hosts are pigs, dogs, cats, etc. Larvae become spirally coiled in the voluntary muscles. It causes trichinosis characterized by nausea, muscular pain, etc.

Dracunculus (Guinea worm). An endoparasitic worm of subcutaneous tissue is digenetic and its secondary host is Cyclops. It causes guinea worm disease characterized by itching, diarrhea, nausea, vomiting, etc. It is the earliest known nematode and was earlier called the “Fiery Serpent.”

Classification Of Animal Kingdom For NEET Phylum Annelida

General characters of Phylum Annelida

• Triploblastic animals.
• Bilaterally symmetrical.
• Found in water and moist soil.
• Mostly free swimming, some are parasites
• True coelom is present for the first time in the animal kingdom. Coelom is shizocoel.
• True metameric segmentation is present.
• Annelids have a complete and straight alimentary canal.
• Annelids show tubes within the tube body plan.
• Locomotory organs are setae or parapodia or suckers.
• In the body wall, both circular and longitudinal muscles are present.
• Blood vascular system closed type.
• Respiratory pigment is hemoglobin, which is dissolved in plasma.
• Respiration either by moist body surface or parapodia or gills is present.
• Nephridia are present for excretion. Nephridia are metanephridia.
• The nervous system consists of a nerve ring, double, solid, ventral nerve cord, and segmental ganglia.
• Sense organs are of many types such as photoreceptors, olfactory receptors, etc.
• Sexes usually united i.e., hermaphrodite.
• Reproductive organs develop from coelomic epithelium.
• Development may be direct or indirect.
• The larva, if present, is a trochophore larva.

Unique features

1. Metameric segmentation
2. True coelom lined by mesodermal epithelium filled with coelomic fluid which acts as a hydraulic skeleton
3. Excretory and osmoregulatory structures are nephridia
4. The presence of circular and longitudinal muscles both in the body wall and wall of the gut
5. Closed circulatory system with respiratory pigment dissolved in plasma
6. Development may be direct or larva if present is trochophore larva.

Classification Of Animal Kingdom For NEET Important Information

Class Oligochaeta

• Chloragogen cells or yellow cells of earthworms are analogous to vertebrate liver cells.
• The brown color of earthworms is due to the pigment porphyrin present in the body wall and coelomic fluid.
• It protects the body from bright sunlight. Lumbricus is the earthworm of Europe and North America; Megascolex is found in South India while Eutypliaeus is found in the Gangetic plain of North India.
• Clitellar glands are maximum in clitellar segments and secrete ootheca.
• Setae are absent in the first, clitellar and anal segments.
• The coelomic fluid of earthworm is with five types of coelomocytes: Phagocytes (largest sized and most numerous); leucocytes, melanocytes, circular cells, and yellow cells.
• Yellow cells, also called chloragogen cells, store glycogen granules so are analogous to hepatocytes of the liver. Some suggest that these are excretory in function.
• Typlilosole: A large-sized fold in the middle part of the intestine and increases the face area of absorption.
• In earthworms, there are 4 pairs of hearts, one pair in each of the 7th, 9th, 12th, and 13th segments. The anterior two pairs of hearts are called lateral hearts, while the posterior two pairs of hearts are called latero-oesophageal hearts.
• Scptail nephridia of earthworm mid nephridia of Nereis arc called metanephridia as each opens In coelom by nephrostome.
• Earthworm In excretion (40% tire).
• In the nerve cord, there are 4 giant nerve fibers which help in reflex actions,
• Receptor organs of earthworms are formed of modified epidermal cells.
• The male reproductive system is formed of two pairs of testes (one pair In each of the 10th and Ith segments) and is enclosed in respective testes sacs (two in number). Prostate glands are one pair while accessory glands are 2 pairs (one pair in each of the 17th and 19th segments).
• The female reproductive system includes one pair of uncovered ovaries (in the 13th segment). Spermal Uecae is 4 pairs (one pair in each of the 6th, 7th, 8th, and 9th segments) and stores the sperms received during copulation.
• Tubifex (blood worm) A darkly red-colored oligochaete (with a large amount of hemoglobin in blood) that can survive even in a highly 02- deficient and polluted fresh-water body.

Important Non-Chordates NEET Questions With Answers

Class Polycliaeta

• Nuchal organs. Olfactory and chemosensory pits on prostomium behind the eyes. These help the worms to detect the prey.
• Gonads are temporary structures and develop only during the breeding season.
• Nephromixia. Nephridia which act as excretory as well as genital ducts. The term nephrotoxic was coined by Goodrich (1945).
• Epiloky. Transformation of a non-sexual into a sexual polychaete. The posterior part of the body with gonads and parapodia with leafy outgrowths and oar-like setae is called epitoke, while the anterior non-modified part is called matoke.
• Trochophore larva is with two ciliated bands: Prtotrocli and telotroch, which help in dispersal
• Aphrodite. Commonly called sea mouse, while Polynoe is called scale worm.
• In Eunice (Potato worm), epitoke is regenerated several times.
• Chactoplertis (Paddle worm) A tuberculous, marine polychacte. It has 3 fan-like notopodia in the middle part of the body which beat and maintain a water current.
• Arenicola (Lugworm), Amphitrite, and Tcrcbella are polychaetes that have gills for respiration.
• Nereis has a closed circulatory system but no heart.

Class Hirudinea

• luminaria granulosa (Indian cattle leech) :
• The skin of leech is with numerous mucus-secreting gland cells.
• A clitellum is formed by the 9th, 10th, and 11th segments during breeding season.
• Nephridiopores are 17 pairs (one pair on the ventral side of each of the 6th to 22nd segments).
• Leech has 3  jaws (jaw with a single row of denticles).
• Hirudin. An anticoagulant in the saliva of leech.
• The crop is the largest part of the gut. It is 10-chambered and stores the blood.
• True coelom in leech is reduced and enclosed in testes sacs and ovisacs.
• Leech has 17 pairs of nephridia and are of 2 types:
• 11 pairs of testicular nephridia (one pair in each from the 12th to 22nd segment).
• 6 pairs of pre-testicular nephridia (one pair in each of the 6th to 11th segments)
• Ciliated organs of nephridia have no excretory function but manufacture coelomic corpuscles of the haemo coelomic system.
• Leech is ammonotelic in excretion.
• Leech has 11 pairs of testis sacs, one pair in each segment from the 12th to the 22nd segment, but has only one pair of ovaries in the 11th segment.
• Spermatophore. Bundle of sperms.
• Pontobdella (skate sucker) is a marine leech that sucks the blood of skates, rays, and sharks.
• Hirtido medicinalis The medicinal leech of Europe is a fresh-water leech.
• Phlebotomy. Method of blood-letting to suck the impure blood by applying an icon-hungry leech to the skin.

Classification Of Animal Kingdom For NEET Phylum Arthropoda

General characteristics of Arthropods

• Habitat. Arthropods are found in all types of habitats. They may be aquatic or terrestrial the insects have taken to the aerial mode of life.
• Germ layers. Triploblastic i.c. ectoderm, mesoderm and endoderm.
• Symmetry. All arthropods show bilateral symmetry, having distinct dorsal, ventral, and lateral sides.
• Body plan. Like all higher animals arthropods show tube-within-tubc plan of the body.
• Level of organization organ system level.
• Exoskeleton. The body is covered by a chitinous exoskeleton which may be impregnated with calcium salts. Chitin is a polysaccharide. The chitinous exoskeleton is largely responsible for the success of arthropods to live on land, it protects the body and prevents the loss of water.
• Body Regions. The body is usually distinguished into the head, thorax, and abdomen.
• The presence of the head is an important advancement and is called cephalisation. In many species, the head and thorax are fused to form a cephalothorax, for Example, Prawn, and Crayfish.
• Segmentation. Arthropods are segmented externally. The segments in the anterior region get fused to form the head. However, the body cavity is not partitioned by septa.
• Jointed Appendages. The most important feature of the phylum is the presence of paired jointed appendages. They are modified according to their function. For example, insects have three pairs of jointed legs on the thorax which are used for walking, in crayfish and prawns they are modified for swimming. Some of them are specialised for feeding while others are applied for sensory and reproductive purposes.
• Wings. The insects are the only non-chordates that can fly due to the presence of two pairs of wings arising from the dorsal side of the thorax. However, some insects, for example, Silverfish and Head louse lack wings. The wings are simply outgrowths of the body wall.
• Digestive system. The alimentary canal opens at both ends of the body and is distinguished into three regions, the foregut, mid-gut, and hindgut.
• Body Cavity. The body cavity is called hemocoel. It lacks a regular layer of mesodermal lining and contains blood.
• Circulatory system. The circulatory system is of open type. The blood directly lies in the body cavity, and there are no closed vessels.
• Respiratory organs. Aquatic forms respire by gills. The terrestrial arthropods such as insects breathe employing certain branched tubular organs called tracheae which ramify throughout the body, and communicate to the outside by certain openings called spiracles.
• Excretory organs. The excretory organs in insects are the malpighian tubules. In crustaceans, the excretion is by green glands or antennary glands.
• Nervous system. It resembles that of annelids and consists of a brain and ganglionated ventral nerve cord.
• Sense organs. The sense organs are well developed. They include compound eyes for sight, and sensilla for smell, hearing, and taste.
• Reproduction. Arthropods reproduce only sexually. Sexes are separate, and the male and female are externally distinguishable.
• Fertilization is internal. Life history usually involves a larva or nymph. The larva (or nymph) later changes into an adult. The phenomenon is called metamorphosis.

Classification Of Animal Kingdom For NEET Unique Features

1. Jointed appendages are modified for performing various functions such as feeding, walking, flight, sensory; copulation, egg laying, etc.
2. The hard exoskeleton of chitinous plates for protection and also provides a hard surface for attachment of muscles
3. Tracheae for respiration in most eases. In other forms gills, book gills, and book lungs act as respiratory organs.
4. Malpighian tubules or coxal glands as excretory organs for excretion.
5. Compound eyes are formed of optical units called ommatidia.
6. Presence of hemocoel

Classification Of Animal Kingdom For NEET Mouth-Parts Of Insects

1. Biting and chewing type Orthopteran Example Grasshopper, cockroaches, crickets, silverfish, Booklice, bird lice, earwigs, termites, Hymenoptera, especially caterpillars, bedbugs, and beetles.
2. Piercing and Sucking
   1. Mandibles, Maxillae constitute needle
   2. Labium – hollow grooved channel Example Mosquitoes
3. Chewing and lapping type Example Honey bees
4. Sponging type Example houseflies and other flies
5. Siphoning type. Butterflies and moths.

Classification Of Animal Kingdom For NEET Metamorphosis In Insects

1. No metamorphosis or Ametabolous development Example silverfish, springtails egg Adult
2. Incomplete metamorphosis or hemimetabolous development
   • Egg → Naiad→ Adult
   • Example Mayflies, Dragonflies, stone flies
3. Gradual metamorphosis or paurometabolous development
   • Egg→ nymph → Moulting Adult
   • Example Grasshopper, Aphids, Stink bug
4. Complete metamorphosis or Holometabolous development
   • Egg → Larva Pupa → Adult
   • Example Housefly, Mosquito, butterfly

Animal Kingdom Non-Chordates NEET Topic-Wise Study Guide

Hormonal Control

1. Brain hormone (BH) – (LIPID)
2. Activates the corpora cardiaca—a component of retrocerebral complex.
3. Prothoracicotrophic hormone (PTTH) is secreted in corpora cardiaca which in turn stimulates Prothoracic glands.
4. Prothoracic gland hormone (PGH) (Ecdysone) Trigger molting.
5. Juvenile hormone (JH)
6. Secreted by corpora allata (non-sterolic lipid). Promotes metamorphosis.

Larvae Of Crustaceans

1. Nauplius—Cyclops. Ii may give rise to intermediate larval forms
2. Mctanauplius—Apus
3. Protozoea—Penacus
4. Megalopa—True crab
5. Glamcothel—Hermit crab
6. Schizopod—Lobster
7. Cypris—Lcpas, Sacculus
8. Alima—Squilla
9. Phyllzosoma—Spiny lobster
10. Zoea.

Classification Of Animal Kingdom For NEET Economic Importance Of Insects

1. Poisonous Insects. Examples are Honeybees, wasps, hornets, fire ants, bed bugs, mosquitoes, and a few lepidopterous and other larvae.
2. Disease carriers
   1. Species of Anopheles spreads Malaria.
   2. Culex mosquitoes spread nematode worm Filaria which causes Filariasis.
   3. Stergomyia mosquitoes spread Yellow fever
   4. Taparus fly spread surra disease among horses and camels.
   5. African sleeping sickness by tse tse fly (Glossina)
   6. Housefly spreads diarrhea, cholera
   7. Fleas spread bubonic plague
   8. Bed bugs and Body Louse spreads Relapsing fever
3. Productive Insects
   1. Honey and bees wax by Honey Bee (Apis indica)
   2. Wax produced by scale insects
   3. Commercial silk by silkworms (Bombyx mori)
   4. Lac is produced by lac insect (Kerria laced)
   5. Shellac secreted by coccidae.
   6. Dyes and tannin are obtained from cochineal dried bodies of certain scale insects.
4. Insects in Medicines
   1. Cochineal Insect contains carminic acid concern, myricetin, fat, and fatty acids used for neuralgia and whooping cough.
   2. Browfly larvae are used in treating the decay of the tissue.
   3. Cantharidine oil obtained from blister beetle,
   4. Bods’ extracts of the cocoon of silk moth used for treating leucorrhoea,
   5. Bee venom is used for
      1. Arthritis and
      2. Antivenom for snake bite
      3. Honey. Natural Antiseptic used to cure ulcers.
      4. Bee wax. Base for ointments.

Classification Of Animal Kingdom For NEET Important Information

• Larvae of the genus Chironomus (an insect) are called blood worms. They have red blood. The red color of these larvae is due to hemoglobin.
• In coastal areas like Konkan Maharashtra of India, the red and black species of scorpions are deadly poisonous. Their venom is fatal.
• Honey is flower nectar mixed with the saliva of bees and is a natural antiseptic.
• Bees communicate by complex dance.
• Royal Jelly—a substance secreted by honey bee workers.
• Termites are social and polymorphic insects.
• Termites form large nests called crematoriums.
• Usually the larger an animal is, the longer it takes to grow up. One exception is the 17-year cicada (an insect), which spends a very long time as a larva.
• In spiders, the web is secreted by the last body segment.
• The thread of the spider web is stronger than steel thread.
• The endoskeleton is present in the head and thorax of the cockroach. The abdomen has no endoskeleton.
• In all insects the intervals between two eedysis (casting of skin) is known as the stadium and the form assumed by the young insect during a stadium is called an Instar.
• Mites are parasites of animals as well as plants
• Fireflies or glow worms bear light-producing organs upon their abdomen. Light is emitted at short intervals by both males and females as a visual signal to attract each other for copulation.
• Gambusia is a larvivorous fish that feeds on up larvae of mosquitoes.

Classification Of Animal Kingdom For NEET Selected Arthropods Class Crustacea

• Daphnia. Its body is covered by a bivalved carapace and is commonly called a water flea.
• Cyclops Commonly called one-eyed monster (with the simple median eye). The female is with ovisacs and carries the eggs. Serves as a vector of Dracunculus nematode.
• Cypris. Commonly called mussel shrimp. A microscopic fresh-water crustacean showing cutaneous respiration.
• Barnacles are sedentary crustaceans Example Liyas. Called a Ship or goose barnacle. A pedunculate crustacean. Carapace is with 5 calcareous plates.
• Balanus. Called Acorn or Rock Barnacle. A sessile crustacean. Carapace is with 5 calcareous plates.
• Sacculina. Called a root-headed barnacle. An ecotoparasite of crab and highly degenerated crustacean due to retrogressive metamorphosis. Induces the development of female characters in infested male crab, called parasitic castration. Squilla is commonly called mantis shrimp as preys upon small marine fishes, crustaceans, mollusks, etc.
• Palinums. Marine spiny or rock lobster as carapace with many spines, Edible.
• Eupagurus (Hermit crab): Shows proto-cooperation with sea anemone (Adamsia).
• Palacmon (Prawn).
  • P. carcinus is giant prawn (90 cm), while P. Lamarr is dwarf prawn (2.5-5 cm).
  • Statocysts (one pair) are organs of balance and lie in the basal segment of each
    antennule.
  • Epimeron. A scaly plate which joins an appendage with the pleuron.
  • Biramous appendage. An appendage in which a basal segment called
  • Protopodite gives two outgrowths: inner endopodite and outer exopodite.
  • Uniramous appendage: When protopodite gives rise only endopodite but there is no exopodite.
  • Cephalic appendages of Prawn are 5 pairs (one pair each of antennules, an tennae, mandibles, maxillidae and maxillae).
  • Thoracic appendages are 8 pairs (5 pairs of legs and 3 pairs of maxillipeds).
  • The digestive gland of crustaceans is hepatopancreas which combines the functions of the liver, intestine, and pancreas.
  • All the gills of Prawn are Phyllobranchcs (gill axis with 2 rows of leafy gill lamellae).
  • The heart of a Prawn is arterial as it receives and distributes oxygenated blood.
  • Prawn shows apposition or mosaic vision in bright light and superposition vision during dim light.
  • Prawn fishery: Capturing of prawns from natural resources as well as their culture.
  • Prawn is a rich source of proteins and A and D vitamins but has low fats. Pcnaeus indicus (about 23 cm. long) is the most important commercial prawn species in India.
  • Lobster tail. The abdominal region of spiny lobsters is used as food.
  • Central Marine Fisheries Research Institute is located at Narakkal (Cochin).
• Oniscus. Only terrestrial crustaceans.

Class Insecta

Sub-class Diplura

• Eleven segments in the abdomen of both immature and adult. Segmented antennae.
• Cerci present, Malpighian tubules absent or vestigial. Primarily wingless. A widely distributed order living in concealed habitats, often in the soil.
• Sub-class Protura Abdominal segments were added successively through post-embryonic growth, making a final complement of eleven segments plus a posterior telson.
• Antennae absent. Malpighian tubules are present but rudimentary. Primarily wingless. Minute, whitish insects widely distributed, found in moist litter, bark, etc.

Sub-class Collembola

• Abdomen with six segments only, usually with three sets of appendages, a ventral tube on segment 1, and a retaining hook on 3 which functions with a powerful springing organ on segment 4. No metamorphosis.
• The tracheal system is absent in most species. No malpighian tubules. Primarily wingless. Living in soil, leaf litter, decaying vegetable material, under bark, etc. Known as the springtails.

Sub-class Apterygota

• Primarily wingless. The metamorphosis from juvenile to adult is slight or absent.
• Mandibles have only a single point of articulation (except in the family Machilidae of the order Thysanura). Usually possessing pregenital abdominal appendages.

Detailed Notes On Non-Chordates Classification For NEET

Cockroach

• Indian cockroach, Blatta orientalis, is dark-colored and small-sized. Female Blatta has vestigial wings.
• The native place of Periplaneta is tropical Africa and not America.
• Burmeister (1838) : Gave the generic name Periplaneta.
• The mouth parts of the cockroach are downward called hypognathous heads.
• The neck, also called the cervical, is not a true body part but is an extension of the arthrodial membrane.
• The labrum is the upper lip, while the labium or second maxilla is the lower lip.
• The hypopharynx is the tongue hanging between the mouthparts.
• Each leg is formed of 5 podomeres. The last podomere is called tarsus.
• Fore wings are thick and leathery and act as tegmina or wing covers.
• Hind wings are the flight organs of cockroaches. Folded like Japanese fans.
• Anal cerci of cockroaches are with auditory receptors.
• The antennae of cockroaches are olfactory and tactile.
• Trichogen cells are seta-secreting cells of hypodermis.
• The rate of heartbeat is 49 times.
• The heart of a cockroach is tubular and 13-clambered.
• Cockroaches and other insects are uricotelic.
• Urate cells of the fat body show excretion by storage.
• Compound eyes show only apposition or mosaic vision. No superposition vision.
• Male cockroach has 3 gonapophyses, called phallomeres, and act as external genitalia.
• Female cockroach has 3 pairs of gonapophyses which act as an ovipositor.
• Each ovary is formed of ovarioles.
• The nymphal stage is called the instar, while the interval between two molts is called the stadium.
• Ecdysis is controlled by ecdysone, a steroid hormone produced by prothoracic glands.
• An adult insect is called an imago and is formed due to the absence of the juvenile hormone of corpora allata of the nymph.
• Cimex lecttilaris (Bed bug). It is an ectoparasite of man, nocturnal in activity, san granivorous (piercing-sucking mouth parts) in feeding, and is found in crevices of cots, etc. The body is sub-circular, flat, and wingless. Each leg ends in two claws. Its bite causes sleeplessness.
• It also spreads germs of typhoid, plague, kala-azar, relapsing fever, etc.
• Pediculus (Head louse). An ectoparasite of man; found glued to the body hair, sanguivorous in feeding with piercing-sucking type mouth parts; spreads typhus fever. The body is flat and wingless.
• antennae are reduced. Mouth parts are piercing-sucking type. Each leg ends into a single claw.
• Pteris (Butterfly). Cosmopolitan insect, diurnal in activity, feeds upon nectar with siphoning type mouth parts, female is oviparous.
• The development includes caterpillar larva and involves complete metamorphosis.
• The body is long and slender. The Head has knobbed antennae, compound eyes, and mouth parts. Thorax has 3 pairs of legs and 2 pairs of wings. The wings have black marks.
• Mayflies. The mayflies are soft-bodied insects with delicate, membranous wings bearing numerous veins and cross-veins, the hind wings much smaller.
• Adults are short-lived, with mouthparts vestigial, short bristle-like term.ro,
• 1 pair of long cerci with many segments, with or without a median caudal filament; adults uniquely preceded by a winged, pre-adult instar.
• Nymphs are aquatic, and active, with paired cerci and a median caudal process, and feathery tracheal gills in most abdominal segments; almost entirely herbivorous.
• Mierotreme (Tennile or white ant). A colonial, polymorphic, and social insect, found in nests called termitaria in woods, 5 castes in the colony (queen, drone, worker, soldiers, and nnsufes); show symbiosis with multiflagellate protozoan Triehonympha.
• Poccilocerus pietus (Ak Grasshopper). It is diurnal, herbivorous (on Ak leaves by chewing-type mouth parts), and flying and jumping (with large-sized senatorial metalegs).
• The female is oviparous and egg-containing cocoons are deposited inside the burrows with an egg-laying apparatus called an ovipositor. The development includes gradual metamorphosis. It produces sound by rubbing the forewings together.
• Crickets. Crickets are medium to large-sized insects, with large prothorax and usually jumping hind legs. Winged or wingless, forewings somewhat hardened to form wing covers (tegmina). Mouthparts mandibulate.
• Cerci is usually short and unsegmented. Females generally with well-developed ovipositor.
• Often with specialized auditor)’ and sound-producing (stridulating) organs. Most numerous in tropical regions, generally worldwide in distribution.
• Generally herbivorous, a few carnivorous.
• Sympctnnn (Dragonfly). It is a diurnal, good flier, and carnivorous (flies and mosquitoes) insect.
• The development includes an aquatic larva called naiad and incomplete metamorphosis. Each forewing has a black spot called pterostigma.
• It is also called a mosquito hawk.
• Damselflies. Damselflies are strong-flying, predacious insects with long, rather narrow wings bearing many veins and cross-veins, hindwings similar to or larger than forewings. The thorax is characteristically modified with legs moved forwards and wings moved backward by tilting the thoracic segments; the abdomen is long and narrow. Generally large insects; a fossil species had a wing span of over 60 cm. Nymphs aquatic, active, predator)’.
• Musea domcstica (Housefly). It is a diurnal and a good flier insect. It feeds upon liquid foods (saprophagous) with its sponging type mouth parts having a fleshy proboscis.
• Hindwings are reduced and are called halters. These act as balancers. The development includes legless maggot larva and complete metamorphosis.
• Aphis brassicae (Aphid). It is a serious plant pest of mustard. It sucks the plant sap with its piercing and sucking-type mouthparts.
• It shows a symbiotic relationship with the ants which are called ant corns. It secretes “honeydew” through their cornicles (honeydew tidies). Tire females are viviparous and reproduce by parthenogenesis.
• Stone pies. Tire stone flies are moderate to rather large, soft-bodied insects with membranous wings, folded over the back at rest, hindwing the larger with a large anal lobe. Antennae are long and hair-like; mouth parts are weak, and mandibulate.
• Abdomen usually with a pair of long cerci. Nymphs are aquatic, active, with long antennae and cerci, and tracheal gills on the thorax, sometimes on the head to abdomen; living only in well-aerated water, mostly vegetarian diet.
• Stick insect and leaf insect. The stick and leaf insects are large, usually of elongated form less commonly flattened, mimicking twigs or leaves. Prothorax is short, and mesothorax is often lengthened. Winged or wingless, forewing often short and hard, and Mouthparts mandibulate. Cerci is short and unsegmented. The ovipositor is small, and concealed. Predominantly tropical distribution; herbivorous.
• Silkmoth. A single cocoon of silkworm provides about 300 metres of silk thread and about 12500 cocoons provide about half a pound of silk. The rearing of silkworms on mulberry plants is sericulture.
• A female lays about 300-500 eggs. In temperate countries, female lavs diapause (dormant) eggs during winter. Caterpillar larva undergoes four molts.
• The pupa is also called chrysalis. India is second in the world in the production of mulberry silk. Central Silk Research Institute is located at Mysore (Karnataka)
• Honey bee. Mouth parts are chewing and lapping types adapted to suck nectar and to mold wax. Prolegs of worker bees with pollen brushes, mesolegs have pollen spurs while metalegs have pollen combs, pollen packers, and pollen baskets.
• Domestication of honey bees is called apiculture while boxes used are called apian/. Domesticated spp.
• include. A. indica (mainly used), A. dorsata, A.florea and A. mcllifera. Inscoutbees, waggle dance was first reported by Karl von Friesch (1956).
• Cicada (Seventeen-yearlocust). With opisthognathous (backward directed head). Not true locust as both pairs of wings are alike (no tegmina). Male producers a very loud and whistling sex call. The metamorphosis period extends upto about 17 years.
• Bugs. The bugs are small to large insects, usually with two pairs of wings, tire forewings of a harder consistency than the hind pair, either uniformly hardened (Homoptera) or with the apical part membranous (Heteroptera).
• Mouthparts modified for piercing and sucking; labium forming a grooved rostrum or snout, containing two pairs of piercing stylets (mandibles and maxillae).
• Many species feed on the sap or cell contents of plants, while others are predatory. Some are important vectors of plant and animal diseases. Distribution worldwide.
• Beetles. Forewings are completely thick and called elytra while hindwings are membranous for flight. Larva has only true legs and is called gnib Examples are Coccinella (Ladybird beetle), Scarabaeus (dung beetle), and Sitophilus (rice weevil — weevil is a grain beetle).

Other Arthropods

• Limulus (horseshoe crab). a living-fossil representative. it is a marine, fossorial, nocturnal, and carnivorous arthropod. locomotion is walking, swimming, and jumping type. body is divisible in cephalothorax (prosoma) and abdomen (opisthosoma).
• cephalothorax is covered by a horseshoe-shaped carapace and has one pair of chelicerae and 5 pairs of legs.
• abdomen has a long spike-like telson at the posterior end and is used for jumping. it is also called “living sil” (about 190 million years old).
• Ticks and mites are parasitic arachnids.
• Scorpion was picturized by Walt Disney in “Living Desert.”
• Mites. Sarcotes (Human itch mite).
• Ticks. Dermacentor (Dog tick), Exudes (Sheep tick), etc. Ticks act as vectors of rocky mountain fever, relapsing fever, etc.
• Muga silkworms feed on Moms.

Classification Of Animal Kingdom For NEET Phylum Mollusca

Characters of Phylum Mollusca

• Body form. The body is a differently shaped head with visceral mass and foot present.
• Habitat Molluscs are generally aquatic (marine as well as freshwater) some of them, for example, slugs and terrestrial while others, for example, Pila (Apple Snail) are amphibious, that is, live in water as well as on land.
• Germ layers. Mollusks are triploblastic animals showing the organ-system level of organization.
• Symmetry. They may be asymmetrical, for Example snails, or may show bilateral symmetry, for Example, Freshwater mussels and cuttlefish.
• Level of organization organ system level of organization.
• Body plan. They show a tube-within-tube body plan. The body cavity includes hemocoel and reduced coelom.
• Body division. The mollusks have soft bodies which are differentiated into three regions foot, visceral hump mass, and head.
• The head bears eyes and sensory tentacles. The foot is the locomotory organ. The visceral hump is the main part of the body and contains various viscera, mainly the alimentary canal, digestive glands, and the circulatory system.
• Mantle and Mantle cavity. The visceral mass is covered by a soft and generally leathery covering called mantle or pallium. Between the visceral hump and mantle lies the mantle cavity which contains the gills and some portions of digestive and reproductive systems.
• Shell. The presence of a hard shell outside the body is a characteristic feature of most die mollusks. The shell is formed of calcium salts and is secreted by the mantle. It varies in shape and size.
• It is spirally coiled in snails (conchs and couriers). In oysters and mussels, it is formed of two equal valves. The shell is light and internal in cuttlefish, while it is absent in some mollusks, for Example, slugs.
• Respiration. The organs of respiration include one or two pairs of gills for aquatic respiration. Aerial respiration through the pulmonary sac. Mantle also plays a role in the process.
• Circulatory system. It is well developed and is of open type.
• The nervous system is well developed. It consists of ganglia, connectives, and commissure.
• Excretion through the renal organ.

Unique features

• There are three body divisions i.e. Head, visceral mass, and ventral foot.
• Body covered by a soft delicate glandular membrane called mantle.
• The space between the mantle and the body is called the mantle cavity.
• Presence of a rasping organ called a radula.
• In most of the forms, the external shell is formed of calcium carbonate and conchiolin present.
• Kidneys are sac-like and open into the coelom at one end and into the mantle cavity at the other end.
• Hectocotylzed arm. The arm of the male cephalopod is modified for transferring spermatozoa into the body of the female’s mantle cavity.
• An octopus is a mollusk without a shell.
• The largest eye is of the Arhiteuthis (Giant) squid measures 15″ in diameter.
• Pearl oysters, the bivalves secrete the pearls.
• A living fossil was discovered in 1952 from a deep trench in the Pacific of Costa.
• Rica and Neopilina show metameric segmentation.
• The segmentation in Neopilina and the presence of trochophore larval stage suggest that mollusks have descended from the annelids.
• An average oyster filters about 3 liters of seawater per hour.
• The study of molluscs is called malacology and that of shells as conchology.
• The term ‘Mollusca’ was coined by Johnston.
• It is the Largest mollusc 55 feet (Giant squid). It is the largest invertebrate also.

• largest tentacles or arms
• Largest shell
• Smallest shell
• Largest snail
• Largest eye of mollusk
• Slowest moving snail
• Largest Octopus
• Largest gastropod
• The slowest growth in mollusk -Deep Sea clam.
• Torsion is the rotation of body points at an angle of 180° about the head and foot.
• The pallial complex is formed by all organs present in the mantle or pallial cavity.
• Mollusc is a first-rate pollution monitor.
• A slug ( a mollusk) is purely an air breather.
• Organs of Bojanus refer to the kidneys of the freshwater mussel.
• Keber’s organs also help in excretion in some giant squids and upload many tonnes in weight.
• The sea butterfly is a mollusk.
• Neopilina, considered a living fossil,
• Ordovician Period “Age of invertebrates” (also called “Age of Giant Mollusca”)
• Spire. All the whorl of the shell except the body whorl.
• Conchiolin: A horny albuminoid protein of shell.
• The innermost layer of the shell is called the hypostracum or nacreous layer or mother of Pearl.
• Nuchal lobes, also called pseudopodia, are formed of mantle. The left nuchal lobe acts as inhaled, while the right nuchal lobe acts as an exhalant siphon.
• Gilt, also called tedium, of Pila is monopetinate (with one row of gill lamel- ‘Iheff’Om gill axis) and pectinibranch.
• The hypobranchial gland is larger in males. Its secretion lubricates the penis and helps copulation.
• Osphradium is a bipectinate structure (with 2 rows of leaflets).
• Radula. A rasping organ in tire buccal mass and has many rows of teeth. The dental formula of each row is 2, 1, 1, 1, 2.
• The digestive gland is the hepatopancreas which performs the function of the liver, pancreas, and intestine.
• Pila has two chambered kidneys which act as a coelomoduct that connects the pericardial cavity (represents true coelom) to the outside.
• Pila is ammonotelic in water and ureotelic on land.
• Loligo (Squid or sea arrow). Similar to Sepia except that the fins are present only in the posterior half and meet posteriorly.
• Octopus (Devilfish). An octopod marine mollusk with 8 sucker-bearing arms but no tentacles. It kills the prey with its poisonous saliva. It has good learning power and can be trained.
• Nautilus has an external, coiled, and chambered shell. It floats by secreting a gas in the chambers. The animal lives only in the last chamber.

Classification Of Animal Kingdom For NEET Phylum Echinodermata

General Characters of Phylum Echinodcrmata

• All members are exclusively marine.
• Triploblastic animals.
• Larva is bilaterally symmetrical, adults become secondarily radially symmetrical (pentamerous symmetry).
• The body bears spines and calcareous ossicles.
• Coelom is cnterocoelic.
• No distinct heart is present.
• Classification of Echinodermata

• Locomotion takes place by tube feet.
• The water-vascular system is a characteristic feature of the phylum Echinodermata.
• The water vascular system helps in locomotion and respiration.
• In some echinoderms, respiratory trees, branchiae, or bursae are present for respiration.
• Coelom is in the form of the haemal system which is concerned with blood circulation. Points.
• The digestive system is simple, alimentary canal is complete.
• No special organs for excretion. Exclusively takes place by amoebocytes.
• Nervous system without brain or central nervous system.
• Sexes are separate.
• The great power of regeneration.
• Fertilization is external, in seawater.
• Development is indirect.
• Larva is pluteus or auricularia or bipinnaria.
• Bilaterally symmetrical larva metamorphoses into a radially symmetrical adult.

Important Information

• The term ‘Echenodermate’ was coined by J. Klein.
• The water vascular system of echinoderms is coelomic in origin.
• The endoskeleton is formed of calcareous dermal ossicles that have mesodermal origin.
• Larvae of echinoderms
  • Dipleura larva. It is the basic larva and all others are derived from it.
  • Bipinnaria larva. Larva of Asteroidea.
  • Auricularia. Larva of holothuroidea.
  • Ophiplecteus larva ophiuroidea. It is the larva of Echinopletcus
  • Doliolaria larva. Larva of sea lilies (Crinoidea)
• Largest starfish-Midgardiaxandaros
• Smallest starfish-Marginastcr carpets
• Aristotle’s lantern-wheel-like saw apparatus of Echinoidea.
• The starfish can open bivalves by attaching two arms with the help of tube feet to either side of a bivalve, pulling it apart. The bivalve tires and opens out.
• The stomach of the starfish is everted through the mouth and introduced into the open mollusk where it is partly digested before being ingested.
• Echinoderms predate on coral polyps also.
• Echinoderms flourished in the Cambrian period.
• Astcrias (Starfish)
• Commonly known starfish are Asterias, Pentaceros, Astropecten, Solaster, Heliaster, Asterina, etc.
• The mouth is also called actinostomc.
• Bivium. Two arms between which madreporite is present.
• Trivium. The remaining three arms of starfish.
• Pedicellariae of starfish are pedunculate and forcipate (with 2 jaws).
• The digestive glands of starfish are 5 pairs of pyloric eerie.
• Digestion is r.vtni corporeal (digestive juices released outside to digest prevent Tietlmnnn’s bodies Nine in number in starfish and probable form the phagocytic amoebocytes.
• Axial gland. Also called Hrougland. Suppose’ to K’ heart,
  The development includes diplexer, bipinnaria, and bracbiolaria larvae.
• The Tornaria larva was first of all discovered by J. Meiller in and was considered by him as the larva of echinoderms, after in 1850.
• Metschnik established that it is a larva of Balanoglossus clavigerus, The name Maria is given to it because of its habit of rotating in circles.

Classification Of Animal Kingdom For NEET Phylum-Hemichordata

Unique features

• Body soft, unsegmented, worm-like, bilaterally symmetrical.
• Triploblastic animals have an organ system level of organization and without appendages.
• The body is divided into proboscis, collar, and trunk which represents the inner tricoelomate organization.
• The digestive tract is complete, either straight with a terminal anus or 11 shape with an anus near the mouth.
• Buccal diverticulum or stomochord. Earlier regarded as notochord present in the proboscis as a hollow outgrowth of the alimentary canal.
• A dorsal heart with two longitudinal vessels (dorsal and ventral) interconnected by lateral vessels and sinuses open type of circulatory system.
• Respiration through one pair to many gill slits or general surface of the body.
  Excretion through proboscis gland or glomerulus.
• Sexes may be separate or united. Life history includes a free-swimming larval stage called tornaria larva.
• Examples-Balanoglossus (Acorn worm or Tongue worm)
• Affinities with chordates Resemblances. Presence of gill slits, dorsal hollow single, non-ganglionated nerve cord ‘and so-called notochord.
• Differences. No chordate character resembles in the true sense. Absence of head, paired app£rida£es. tail, endoskeleton, and presence of single-layered epidermis, Affinities, and echinoderms
• Both have poorly developed nervous system
• Both have the same pattern of coelom and open out and filled with water.
• The Larva of Balanoglossus named tornaria resembles the bipinnaria larva of starfishes

The cellular grade of organization can be observed in all protozoans. Animal cells are diverse in structure and function lack a rigid cell wall and are quite flexible. Based on the complexity of the organization metazoans are divided into two subkingdoms i.e. Parazoa and Eumetnzoa.

• Coelom formation in schizocoelomata takes place by the splitting of mesodermal pouches present on the lateral sides of the prospective gut and in enterocoelomata by the growth of lateral mesodermal pouches from the endoderm.
• The animal kingdom includes about 35 phyla of which
  11 are considered major phyla.
• About 99 percent of animals are invertebrates and the remaining represent vertebrates.
• Unicellular protists animals are included in protozoa and about 15,000 species are known.
• Locomotory structures of Protozoans are flagella, cilia, pseudopodia or absent as in sporozoa.
• Euglena, Amoeba, Paramecium, Noctilucn, and Elphidium are free-living protozoan, Monocystis, Entamoeba, Plasmodium, Trypanosoma and Giardin are parasitic protozoan.
• The size of theifiers ranges from l cm to l meters in length. Some members of porifers are radially symmetrical but huger ones are asymmetrical.
• Sponges reproduce asexually by fragmentation or budding.
• Sycon (scypha), Spongilla, Proterion (Neptune’s cup), Cliona (Dead man’s finger).
• Euspongia (Bath sponge) and Euplectellu aa common examples of sponges.
• Cnidarians exhibit two basic body forms, the Polyp (fixed and feeding) and medusa five swimming and reproductive Coclenterates (Cnidarians) show polymorphism.

NEET Biology Enzymes

Enzymes. serval definitions given for enzymes are as follows:

• The catalyst in living cells facilitates metabolic reactions.
• The enzymes arc directing and controlling catalysts that determine the particular chemical reaction which makes up the complex metabolic pattern of living organisms.
• A protein with catalytic properties due to its power of specific activation.
• Enzymes are organic catalysts.

Enzymes are proteinic substances that act as biological catalysts with a high degree of specificity produced within the cell having an enormous ability to catalyze all metabolic reactions in a highly effective manner. Enzymes may be simple proteins or conjugated proteins formed of apoenzyme (protein part) and cofactor (prosthetic group or coenzymes or metallic cofactor). Å

Read and Learn More NEET Biology Notes

Enzymes NEET Notes

Discovery of enzyme

• Edward Buchner (1897) showed that the juice of groundnut and preserved yeast cells ferment sugar.
• The Tenn enzyme was coined by VV. Kuhne.
• J.B. Sumner purified and crystallized urease enzymes from Jack beans. He also suggested that enzymes are proteins.

Properties

• Enzymes function as catalysts, necessitate minimal quantities, exhibit great specificity, and perform optimally at temperatures ranging from 25 to 40°C; low temperatures impede activity, while elevated temperatures lead to denaturation.
• Enzymes necessitate an optimal pH tailored to each individual enzyme. The ratio of enzyme to substrate concentration influences the reaction rate.
• Certain inhibitors impede enzymatic activity. Extracellular enzymes are synthesized in inactive forms known as proenzymes.
• Certain enzymes exhibit minor variations in molecular structure yet execute identical functions; they are referred to as isoenzymes or isozymes.
• For instance, lactic dehydrogenase, which catalyzes the conversion of pyruvate to lactate, possesses five more isomeric forms.

Mechanism of action. Fischer (1894) suggested the Lock and Key hypothesis.

Koshland Induced Fit Theory. Lock and Key Theory (Contemplate theory) has been modified and accepted as induced fit theory. This suggests the existence of two groups i.e. buttressing or supporting and catalytic groups on the active site enzyme.

As the substrate gets associated with the buttressing region, the active site changes configurations so that the catalytic group comes to lie opposite to the area where substrate bonds are to be changed.

NEET Biology Nomenclature And Classification Of Enzymes

According to the International Union of Biochemistry (I.U.B—1961) system of classification.

1. Reactions and enzymes catalyzing them are divided into 6 major classes each with 4- 13 subclasses.
2. The enzyme name has two parts—the first name is the substrate. The second ending kinase indicates types of reactions.
3. The enzyme has a systematic Code No. (E.C.). The first digit denotes the class, the second sub-class, the third sub-sub class and the fourth one is for the particular enzyme name.

Thus E.C.2.7.1.1 denotes class two (transferases)-subclass- 7 sub-subclass 1 fan alcohol function as phosphate acceptor). The fourth digit indicates hexokinase.

Enzymes NEET Notes

Major Classes of Enzymes

1. Oxidoreductases. Formerly known as oxidases and dehydrogenase
2. Transferases. Catalyze transfer of one carbon group, aldehyde or ketone, or functional group.
3. Hydrolases. These enzymes cause cleavage of a variety of bonds by the addition of water.
4. Lyases result in the direct removal of groups from the substrate or the break of the bonds without the addition of water.
5. Isomerases. Which catalyze isomeric changes.
6. Ligases or Synthetases. Catalyze linking together of different types of bonds.

NEET Biology Some Terms Regarding Enzymes

Isozymes (Isoenzymes):

Enzymes execute identical duties yet exist in several molecular forms within the same tissue or organ.

For instance, lactate dehydrogenase (LDH) comprises five isoenzymes, while alpha-amylase contains sixteen isoenzymes.

• Denaturation: A process or series of actions that alters the structural configuration of the polypeptide chain of a protein molecule from its original state to a more disordered arrangement. The denatured enzyme exhibits no enzymatic activity.
  Holoenzyme. The enzyme complex is referred to as a holoenzyme.
• Apoenzyme: The protein component of the holoenzyme is thermolabile and colloidal.
• Allosteric locus: A segment of the enzyme where a specific effector or modulator may bind, which can exert either positive or negative effects.
• Allostery (Allosteric inhibition): Modulator-induced alteration of the active site, hence inhibiting substrate binding.

Factors Affecting Enzyme Action

• Effect of enzyme and substrate concentration. Raising the concentration of enzyme increases the rate at which substrate is converted to product, but at high substrate concentration, the enzyme molecules become saturated.
• K1: Disassociation constant of enzyme-inhibitor complex. It applies to competitive inhibitors. Lower K1 is essential for enzyme activity, and higher decreases it.
• Michaelis Constant. (Km) Leonor Michaelis and Mand Menton (1913). It is a constant that indicates the substrate concentration at which the chemical reaction catalyzed by an enzyme attains half of its maximum velocity. The lower the value, the higher the affinity of the enzyme for the substrate.
• Effect of pH. The pH sensitivity of an enzyme depends on how many ionizable R groups are necessary for its activity and its charge. Generally, enzymes function at near-neutral pH.
• Effect of temperature. Temperature above 60°C denatures most proteins or disrupts
  their structure. At low temperatures, enzymatic reactions proceed slowly. The optimum
  temp is 25- 40
• Some blue-green algae live on the surface of glacial ice and have enzymes adapted to temperatures close to freezing point.
• Some bacteria inhabit hot sprigs of the Yellow Stone Park and their enzymes are adapted to function at temperatures 80-85ºC

Classification Of Enzymes NEET Biology

Regulation of Enzyme Action

1. Control at the enzyme level. level DNAl so is termed master feedback.
2. Control at the gene level. molecule inhibition which controls or negatively the feedback synthesis of proteins and therefore enzymes. Proteins are the end products of gene expressions.

NEET Biology Commercially Important Enzymes

1. The biological washing powder enzyme used is Proreases.
2. In brewing, amylases found in germinating barley digest starch in the grain to form malt sugar (maltose).
3. This sugar is fermented by yeast during brewing
4. Amylases used in dishwashing powder remove starch smears from utensils.
5. Rennin plays a role in curdling milk thus helping in cheese making.
6. In leather making, proteases remove hairs from the hide.

Significant Historical Facts of Enzymes

• Krichoffiis (1815): First indicated the occurrence of enzymes in a living system.
• Louis Pasteur (1860): Fermentation of foodstuffs can be brought about by yeast cells.
• Kuhne (1878): First gave the term ‘Enzymes’.
• Buchner (1897): First prepared a pure extract of zymase enzyme from yeast.
• Sumner (1926): Found enzymes to be proteinaceous, crystallized enzyme urease from Jack beans (Canavalia ensifonnis)
• Northelop (1930): Pure crystals of enzyme pepsin and trypsin from gastric and pancreatic juice.
• Monod et al (1965): structure of Allosteric enzymes. These enzymes do not obey Michaelis Menton’s constant i.e. constant.
• Lock and Key hypothesis was given by Emil Fischer (1894) and modified by Koshland (1971) as induced fit theory.
• Arber Nathans and Smith: discovered, the enzyme Restriction Endonuclease.
• Cecil et al (1981) in ribozyme and Altaman et al (1983) for ribonuclease —P found enzyme activity to be present in RNA. (Non-proteinic enzyme) 03 Hansen—Isolated renin Indicate Nobel Laureate.

Classification Of Enzymes NEET Biology

• Enzymes are biological catalysts.
• All enzymes have a specific three-dimensional structure, a part of which is known as an active site.
• An enzyme may have more than one active site.
• Formation of carbonic acid (H2, CO3) from CO, and H,0 in the presence of carbonic anhydrase is 10 million times faster than the non-catalysed reaction.
• Each enzyme can catalyze the change of either a specific substrate or a specific group of a substrate.
• Each enzyme shows its highest activity at a specific pH.
• Cyanide kills an animal by inhibiting cytochrome oxidase, a mitochondrial enzyme essential for cellular
• Respiration. It is an example of non-competitive inhibition of an enzyme.
• The decline in enzyme activity by the allosteric effect of the product is called feedback inhibition Example allosteric inhibition of hexokinase by glucose-6-phosphate.
• Competitive inhibitors are always reversible.
• Non-competitive inhibitors may be reversible or permanent.
  c& Non-reversible inhibitors are always non-competitive.
• According to the Michaelis-Menten equation Km is equal to substrate concentration at which half of maximum velocity is achieved. Michaelis and Menten proposed a
• Hypothesis For Enzyme Action According to the enzyme molecule combines with a substrate complex which further dissociates to form a product and enzyme back
• \(\mathrm{E}+\mathrm{S} \underset{K_2}{\kappa_1} \mathrm{E}-\mathrm{S} \rightarrow{K_3} \mathrm{E}+\mathrm{P} ;\)
• Km (Michaelis-method constant)= \(=\frac{K_3+K_2}{K_1}\)
• They gave the following equation: 
• \(V_o=\frac{V_{\max }(S)}{(S)+K_m}\)
• It is the statement of the quantitative relationship between the initial velocity Vo, the maximum velocity Vmax, and the initial substrate concentrations: all related through Michaelis Menten constant Km
• H- free enzyme
• S = substrate
• HS = enzyme-substrate complex
• I = product
• K1= (he rate constant for ES formation
• K2 = the rate constant for the dissociation of ES into E and S
• K1 is the rate constant for the dissociation of the ES complex into ES and P.

Mechanism Of Enzyme Action NEET Study Material

Quanta to memory

• Kuhne (1878) coined the term enzyme.
• Buchner ( 1897) isolated enzymes for the first time. All components of the cell including the cell wall and cell membrane have enzymes.
• Mitochondria contain a maximum number of enzymes in the cell. (70%)
• The smallest enzyme is peroxidase and the largest is catalase found in peroxisomes.
• Enzyme activity increases from 0°C to optimum temperature and doubles with every 10° rise in temperature. This is called the temperature coefficient (Q10)
• Chemozymes are chemically synthesized enzymes.
• The highest turnover number is of the enzyme carbonic anhydrase. (36 million) with Zn++ as. activator.
• The lowest turnover number is of enzyme lysozymes.
• Mental Activators 
• Na for AT Pase
  Fe „ Catalase, aconitase, cytochrome oxidase
  Zn „ Carbonic anhydrase
  Mg „ Hexokinase
  Mo „ Nitrate reductase
• Enzyme urease isolated from Jack bean Canavalia was crystallized by Sumner in 1926, who proved the protein nature of enzymes.
• Enzymes show 3-D structure.
• Enzymes work in milliseconds and the rate of enzyme of the substrate is as high as 1: 10,00,000.
• Now RNA with catalytic and synthetic functions has been found in a protozoan Tetrahymena thermophila.
• The smaller the Km, the greater the substrate affinity.

Turn over Numbers

• Metal Activators
• Carbonic anhydrase = 3.6 x 106
• Acetyl cholinesestrase = 1.5 x 106
• Urease = 1.0 x l06
• Amylase = 10 x 10s
• Lactic acid dehydrogenase = 6.0 x 104
• Chymotrypsin = 6.0 x 103
• Lysozyme = 3.0x 101

Enzymes Identified with Hereditary Disease

NEET Biology Kingdom Monera Main features

It encompasses all prokaryotic species, with size ranges of 1-10 µm, including cyanobacteria (blue-green algae) and bacteria.

• Prokaryotic cells are distinguished from eukaryotic cells by possessing a cell wall composed of complex substances (excluding cellulose and chitin), circular bare DNA, and the absence of membrane-bound organelles such as mitochondria.
• Some prokaryotes possess internal membranes, such as lysosomes in certain bacteria, and membrane systems that house enzymes for photosynthesis and respiration.
• Prokaryotes reproduce via binary fission.
• Cyanobacteria do not exhibit sexual reproduction; rather, genetic recombination in certain bacteria transpires through conjugation, transformation, and transduction.
• Numerous prokaryotes produce spores in response to unfavorable conditions.

Read and Learn More NEET Biology Notes

• Their small size, metabolic diversity, and rapid reproduction probably account for the evolutionary success of prokaryotes.
• Classification of Kingdom Monera. Simple prokaryotic cell structure, unicellular, both heterotrophs and autotrophs. Kingdom Monera was created by Copeland (1966), and divided into three main groups.
• Schizomycophyta (Bacteria) smallest living cells, basically unicellular, with indistinct nuclei, colorless, and mainly heterotrophic Examples; are Cocci, Vibrio, Bacilli, Spirilla.
• Cyanophyta or Cyanobacteria (Blue-green algae). Unicellular, no distinct nucleus, blue-green color e.g. Oscillatoria, Nostoc, Gloeoccipsa, Tolypothrix.
• Archaebacteria. Most primitive prokaryotes are considered to evolve immediately after the evolution of first life, The cell wall lacks peptidoglycan but contains protein and non-cellulosic polysaccharides. Branched-chain lipids in membrane. Live under hostile conditions Example; Methanogens, Halophiles, and Thermoacidophiles.

Kingdom Monera NEET Notes

NEET Biology Kingdom Monera Bacteria

• Bacteria are very small and their size generally ranges from 0.2 – 1.5 pm in diameter and 2 – 10, pm in length.
• Dialister pneumonsinilis is the smallest bacterium (0.15 — 0. 3 pm long); Bacillus buischili (80 pm long, 3 — 6 pm, diameter); Beggiatoa mirabilis is the largest bacterium (16 — 45pm diameter and upto several centimetres long).
• Bacteria occur in three basic forms or shapes. These are either spherical (cocci), rod-shaped (bacilli), or spiral (vibrio/spirillum). Though most bacterial species have cells that are of a fairly constant and characteristic shape, some species are pleomorphic (i.e.; these can exhibit a variety of shapes).
• Gram staining, introduced by Christian Gram in 1884, divides bacteria into two groups: Gram-positive and Gram-negative.
• Flagella (sing, flagellum; Latin whip). Long (3 — 12 pm), fine, wavy, filamentous appendages that protrude through the cell wall, responsible for the motility of bacteria.
• These are much thinner than the flagella or cilia of eukaryotes, being 0.01 to 0.02 pm in diameter.
• Bacteria may be atrichous (without flagella), monotrichous (with one flagellum), lophotrichous (with a group of flagella at one end), amphitrichous.
• Two flagella (also two groups of Flagella), one at each end Example; Alkaligenes feces and peritrichous (flagella present all over the body) ccphalotrichous—(Two or more flagella at one end)
• Pili or Fimbriae (Sings. Pilus = hair fimbirae = fringe). These are hollow, nonhelical, filamentous appendages projecting from the walls of some gram-negative bacteria.
• These are thinner and shorter; and more numerous than the flagella. These also arise from the basal body and are made up of specific proteins called pilin.
• Some bacterial cells are surrounded by a viscous substance forming a covering layer or envelope around the cell wall. If this layer is in the form of a loose mass, it is called slime.
• Below the external structures like capsules and flagella; and outside the cell membrane is present a rigid structure called a cell wall. Due to its rigidity, it protects the internal structures of the cell and provides shape to the cell.
• However, its main function is to prevent the cell from expanding and bursting (Most bacteria live in hypotonic environments, and are likely to take in much water and eventually burst).
• The cell walls of almost all the eubacteria (true bacteria) are made up of peptidoglycan, also called murein or mucopeptidc. It is found only in monerans.
• The plasma membrane is a phospholipid membrane also containing proteins and polysaccharides. It is selectively permeable. The respiratory enzymes are associated with the cell membrane as the mitochondria are absent.
• Mesosomes. The cytoplasmic membrane is invaginated at certain places into the cytoplasm in the form of the system of convoluted tubules and vesicles, (mesosomes).
• On their surface are found enzymes associated with respiration. Therefore, these are supposed to be analogous to the mitochondria of eukaryotes.
• The cytoplasm is a complex mixture of amino acids, proteins, lipo-complexes, nucleotides, carbohydrates, vitamins, and coenzymes.
• The membrane-bounded organelles like endoplasmic reticulum, mitochondria, and Golgi bodies are absent in bacteria. However, ribosomes are present in sizeable numbers, providing a granular appearance to the cytoplasm.
• The cytoplasm contains about 10,000—30,000 ribosomes of the 70 S type. The sedimentation coefficient of bacterial ribosomes is 70S. Each ribosome consists of 2 unequal subunits (30S and 50S). Each subunit is composed of RNA and protein.
• The most common non-living inclusions in the cytoplasm are —volutin granules, PHB, and elemental sulfur. The volutin granules, also known as metachromatic granules, are polymetaphosphates and serve as a reserve source of phosphate.
• PHB. (Poly (3 hydroxybutyrate) is a lipid-like material and can serve as a reserve carbon and energy source.
• Some bacteria that live in aquatic habitats form gas vacuoles which provide buoyancy to the cells.
• As compared to the eukaryotes, bacteria do not contain a distinct membrane-bounded nucleus and all other membrane-bound organelles are absent.
• However, an amorphous lobular mass of fibrillar, chromatin-type material that occupies about 10 — 20% of the cell, is present near the center of the cell.
• DNA of the cell is confined to this area called nucleoid or chromatin body or nuclear equivalent or genophore.
• It is also called a bacterial chromosome as it consists of a single, circular DNA molecule in which all the genes are linked.
• This single molecule is over a thousand times longer than the cell itself and is, therefore, highly folded. Bacteria generally lack the histone proteins.
• In addition to the normal DNA chromosome, some extrachromosomal genetic elements are often found in bacteria. These elements are called plasmids.
• These are circular pieces of DNA that have extra genes. These are capable of autonomous replication in the cytoplasm of the bacterial cell.
• Plasmids carry genes responsible for different functions in bacteria. For example, Rfactor plasmids (which confer resistance to antibiotics), colicincrgic factors (responsible for the formation, in coli. of special proteins that kill closely related species of bacteria) of genes (for nitrogen fixation).

Reproduction

It takes place by binary fission with the cell dividing at right angles to its long axis. The following steps are involved:

1. Division of nuclear material. After the bacterial cell has attained maximum size, the nuclear material duplicates and divides without any spindle formation. The DNA is found attached to the mesosomes near the septum-forming region.
2. Cleavage of the cytoplasm. The cell membrane from the middle part of the cell grows inwards dividing the cytoplasm into two halves.
3. Formation of cross wall. In between the two newly formed cytoplasmic membranes, a cell wall (septum) is laid down, forming two daughter cells.
4. Separation of daughter cells. The growth of the two daughter cells creates tension that separates the two newly formed cells.

Bacteria Classification NEET Exam

Transfer of genetic material (Genetic recombination) 

1. Conjugation. Investigations with an electron microscope have shown that two E. coli cells can conjugate and the genetic material (DNA) from one cell can be transferred to the other. The sex difference between the Z (donor) and Z (Recipient) cells is determined by the presence or absence of a specific genetic factor called F (fertility factor. When present, F is a donor cell, and when absent, F-, is a recipient cell. The F factor can exist in two alternative states—as part of the E. coli chromosome or as a very small free DNA strand.
   • The £. coli strains are then (high-frequency of recombination) or metafile and F strains respectively.
   • Conjugation occurs between an Hfr and a cell or between a P and a Pcell. The P cells transfer only the F factors after its replication.
   • The cells transfer both the F factor as well as the genetic constitution of the donor cell. The recipient cell now becomes a merozygote (partially diploid).
2. Transformation. A genetic change takes place in the recipient bacterial cell as a result of the absorption of DNA fragments reduced
3. Transduction. It is a process in which fragments of UNA are carried by bacteriophages train one bacterial cell to another. It was first observed by Zander and Lederherg (1952).

NEET Biology Kingdom Monera Economic Importance Of Bacteria

Cyanobacteria Characteristics NEET

NEET Biology Kingdom Monera Actinomycetes

These microorganisms connect bacteria with fungus. Similar to mushrooms, their somatic architecture comprises multicellular filaments (hyphae) that collectively constitute the mycelium.

• They were previously referred to as “Ray Fungi.” They generate asexual spores, referred to as conidia, on aerial hyphae, which serve as asexual spores in fungi, in contrast to bacterial endospores.
• They are thermally inactivated and not thermally resistant. Their spores and cells do not exceed 2 to 3 microns in diameter.
• Actinomycetes are either saprophytes or parasites. Certain organisms, such as Streptomyces spp., thrive in the soil.
• Conversely, several species, such as Micromonospora spp., are only located in semi-aquatic environments, specifically among lacustrine muds.
• Certain members, like as Nocardici spp., are recognized for their ability to breakdown substrates including paraffin, phenol, and petroleum-derived compounds, which are very resistant to most bacteria.
• Actinomycetes spp. are specialist parasites located in the oral cavities of animals. Reproduction through fragmentation or conidia.

Archaebacteria Features NEET Study Material

Economic Importance

The genus streptomyces of this group is most important, some species of which produce antibiotic substances of great medicinal value like streptomycin, chlorotetracycline, oxytetracycline, tetracycline, chloramphenicol, and erythromycin.

NEET Biology Kingdom Monera Chlamydiae

These are the smallest recognized bacteria and are subgroups of rickettsiae which cause diseases in humans and animals. They have DNA, RNA, and some enzymes. They can be treated with some antibiotics.

The two species of chlamydiae are:

Chlamydia trachomatis causes trachoma in the eyes and two sexually transmitted diseases such as chlamydial urethritis and lymphogranuloma encrust.

Chlamydia psittaci which causes psittacosis in birds. L-forms. Klieneberger discovered L-forms during the culture of Streptobacillus moniliformis.

being the initial of the Lister Institute named for Lord Lister (a pioneer in aseptic surgery). These micro-organisms lack cell walls and are produced only by Bacillus.

L-forms can be converted again into Strcp-tobacilliis. L-forms can be selected by cultivation of bacteria in an osmotically buffered penicillin-containing medium.

Therefore, L-forms arc bacteria in which the primer for peptidoglycan has either been eliminated or modified by penicillin treatment.

They are found in water and mud as free-living organisms. They form a small group of heterotrophic bacteria. Most of the spirochaetes are parasites of man and animals.

They are unicellular and helicoid in shape. The cell has two overlapping sets of fibrils.

The protoplasm is enclosed by a flexible cell wall.

Spirochaetes cause some human diseases as Syphilis is caused by Treponema pallidum Relapsing fever by Borrelia Jaundice (infectious) by Leptospira

NEET Biology Kingdom Monera Archaebacteria (Ancient Bacteria)

They are highly primitive and inhabit exceedingly inhospitable environments where few other species can endure.

• Certain organisms are anaerobic and generate methane, while others inhabit highly saline environments or thrive in hot, acidic sulfur springs.
• Their cell wall lacks peptidoglycan.
• They have special branched-chain lipids in their cell walls which make them heat and acid resistant.

Differences between cyanobacteria, halophiles, and thermoacidophiles

Gram-Positive vs Gram-Negative Bacteria NEET

Differences between Gran +ve and Gram -ve bacteria

Prokaryotic Cell Structure NEET Biology

• Mirco-organisms like bacteria sometimes can exist without a cell wall. The hu-cell membrane and its intact contents are then called protoplasts (osmotically fragile). Young actively growing gram (+) bacteria are sensitive to penicillin. So. these bacteria can Be made of protoplasts.
• The nrehacbactcria and bacteria possibly arose from a more ancient form of life called progenitor. Understanding one kind of organism requires the isolation of one individual and multiplying or culturing it. i.e. to obtain pure culture.
• A pure culture contains multiple copies of a single kind of micro-organism. The microbiologist has developed several techniques to obtain the pure culture of microorganisms.
• All eubacteria have a cell wall, made up ofmurein or peptidoglycan. It consists of polysaccharides cross-linked with short amino acid chains. Bacterial conjugation though different from eukaryotic sexual reproduction is a means of making new genetic combinations that are expressed as progeny.
• Rhizobium is a symbiotic nitrogen-fixing bacterium. The non-symbiotic free living nitrogen-fixing bacteria are Azotobacter, Beijerinckia, and Klebsiella (all aerobic) The non-symbiotic free living anaerobe, nitrogen-fixing bacterium is Clostridium pasteurianitm.
• Chromalium. Rhodospirillum arc photosynthetic nitrogen-fixing bacteria. E. coli bacteria are present in the large intestine of humans and mammals. They are straight rods. There are motile and non-motile types of E.coli.
• The cell surface has pili on which certain phages are absorbed. E. coli is a facultative anaerobe. The optimum temperature for its growth is 30-37 °C and the optimum pH value of medium is 7.2— ca> 7.5.
• Nosloc sp. occurs within the tlialli of Blasia and Anthoceros (The Bryophytes). Nostoc sp. lives within the cells of Gcosiphon pyreforme (a fungus) Nostoc sp. occurs in the petiole of Gunnera (an angiosperm). Calothrix sp. lives within the cells of Enteromorpha (a green alga).
• Trifolium alexandrinum (Clover) contains Nostoc in its nodules. The reddish color of the Red Sea is due to a cyanobacterium Trichodesmium erythraeum.
• Cyanobacteria associated with Protista. Death factors VFDF (very fast). FDF (fast) and SDF (slow) are toxins produced by cyanobacteria. Biological nitrogen fixation has been discovered by Winogradsky.

• The smallest cocci range from 0.5 pm to 1.5. pm in diameter while spiriJJi are as large as 60pm (Peberdy, 1980). About one trillion (1 012) bacteria of average size could be packed into a 1 ml pipette.
• A single drop of water may contain as many as 50 thousand million bacteria. A teaspoonful (5 ml.) of packed bacteria represents 2000 times as many individuals as there are people on Earth.
• A tea .spoon of rich soil contains billions of bacteria Mycobacterium and Xanthomonas form nodules in the leaves of Ardisia and Puvetta while Frankia forms nodules in the roots of Alms and Casuarina.
• Gram-negative bacteria are usually partly or wholly resistant to penicillin.
• When Gram-positive bacteria are treated with lysozyme (found in egg white, secretion of skin and mucous membranes and tears) they are rapidly denuded of their cell walls and become naked protoplasts while the peptidoglycan cell wall of Gram-negative bacteria is protected by an outer layer of lipo-complex (it can be removed by ethylene diamine tetra acetate or EDTA).
• So the cell wall of Gram (—) bacteria is not completely re¬ moved. Such only partially denuded cells are called spheroplasts.
• The cell walls of Gram-positive and Gram-negative bacteria differ in their chemical composition. In Gram-positive bacteria, the cell wall has a thick peptidoglycan layer that comprises 90 percent of the cell wall.
• The cell walls of gram-negative bacteria are much more complex. The peptidoglycan layer is very thin making up only 10% or less of the cell wall.
• However, the most interesting feature is the presence of an outer membrane that covers a thin underlying layer of peptidoglycan. The outer membrane is a bi-layered structure consisting chiefly of phospholipids, proteins, and lipopolysaccharides (LPS).
• Due to the presence of the outer membrane, Gram nega¬ tive bacteria are rich in lipids that make up about 11-12% of the dry weight of the wall. Teichoic acid is absent.
• The cells of certain bacteria like Aquaspirillum magnetotacticum contain structures composed of iron in the form of magnetite (Fe304). These are called magnetosomes and help bacteria orient themselves along the geomagnetic lines.

NEET Biology Cell Unit Of Lift And Structural Organisation

All living organisms consist of many coordinated compartments known as cells.

1. Robert Hooke (1665) was the inaugural individual to employ the term ‘cell.’
2. In 1831, Robert Brown identified a nucleus within orchid roots.
3. Cytology: The discipline focused on the scientific examination of cells is known as cytology.
4. The inception occurred in the early 17th century with the initial utilization of microscopes by Hooke, Grew, and Malpighi.
5. Cellular biology: A comprehensive examination of a cell, considering its structure, functions, biochemical characteristics, reproduction, energy dynamics, division, development, and differentiation.
6. Cell theory: German scientists Schleiden and Schwann proposed the cell theory, which asserts that all living organisms consist of cells.

NEET Biology Cell Unit Of Life Present Day Concept Of Cell Theory

1. The body of almost all living organisms is an assemblage of cells or the cell constitutes the structural unit of all living organisms.
2. Each cell represents a unit of metabolic activities because all the characteristics of life are performed within the cell.
3. Cells are hereditary units also as they contain hereditary materials inside the nucleus.
4. New cells originate from pre-existing cells. (R. Virchow 1858).
5. All the activities are the outcome of the activities of its constituent cells.
6. All the cells are capable of independent existence and they work as autonomous units.
7. In multicellular organisms, a clear-cut division of labour can be noticed. However, cells are still dependent partly on each other.

Read and Learn More NEET Biology Notes

Cell The Unit Of Life NEET Notes

Cellular totipotency is the ability of a somatic cell of a plant to produce a new complete plant.

• Steward et al. showed the phenomenon of cellular totipotency in carrot cultures,
• Unicellular organisms are capable of performing all the metabolic activities.
• For an efficient cell, the ratio of volume to surface area should be high.
• A cell represents itself in two forms i.e. as an individual and as part of the continuity of cells.
• Multicellular organisms are adapted for better survival.
• Growth and synthesis of protoplasm are due to the nucleus of the cell.
• Cytoplasm (mesoplasm cytosol or kinoplasm) is protoplasm except nucleus.
• Protoplasm is a reversible crystallocolloidal solution. Term cytoplasm was given by Kolliker.
• Hyaloplasm is cytoplasm outside the nucleus.
• Cytoplasm coagulate when treated with acids/bases or heated above 60°C.
• AH, physical and chemical changes tend to proceed in such a direction that useful energy undergoes irreversible degradation into a random form called entropy.
• pH (powered hydrogen) or puissance hydrogen of cytoplasm, nucleoplasm and human blood is 6.9 ± 0.2, 7.4 ± 0.2 and 7.34 ± 0.2 respectively.

NEET Biology Cell Unit Of Life Types Of Cell

Prokaryotic cell. A primitive cell which lacks a nuclear membrane, or nucleolus, possesses 70S ribosomes, membrane-bound organelles absent, and naked DNA present, also called a nucleoid or genophore or chromosome or fibrous nucleus or incipient nucleus, Example Bacteria, Blue green algae, PPLO etc.

Mesokaryotic cell. It is characterized by the absence of deoxyribounyleohistone; however, well well-defined nucleus is present. A peculiar type of division called dino mitosis occurs. Dodge used the term for cells of dinoflagellates (a type of algae). Eukaryotic cell.

Present in higher organisms. It possesses a true nucleus, DNA is associated with histone proteins called chromatin. Membrane-bound cell organelles present.

Cell Structure and Its organelles

• A cell is a specific combination of organelles and is usually a microscopic bit of complex organized matter.
• Cytoplasm is a complex mixture of organic and inorganic matter. It is amorphous and gel-like, containing various organelles.
• The part of the cytoplasm outside the organelle is called cytosol which contains a system of microfilaments. It acts as a store of vital chemical activities and also as a site of certain metabolic activities like glycolysis and biosynthesis of fatty acids and certain proteins.
• Cytoplasmic streaming or cyclosis helps in the formation of pseudopodia and the movement of organelles and other cell inclusions.

NEET Biology Cell Unit Of Life Cell Organelles

Cell organelles are of the following types depending upon several membranes.

1. Single unit membrane-bounded organelles. Microbodies (Peroxisomes, Glyoxysomes, Sphaerosomes, Lysosomes, Golgi bodies, ER, vacuoles.)
2. Double unit membrane-bounded organelles. Plastids, Mitochondria and Nucleus.
3. Amembranous organelles: Ribosomes, centrioles, spindle, microfilaments and microtubules.

Endoplasmic Reticulum

The endoplasmic reticulum [ER] consists of an interconnected system of membrane-bound channels in the cytoplasm. It forms 30 to 60% of the total membranes of eukaryotic cells.

Electron microscopic observations by Porter, Claude and Fullam (1945) revealed a network of delicate strands and vesicles in the cytoplasm. The term endoplasmic reticulum was first used by Porter and Kallman (1952).

The endoplasmic reticulum consists of cisternae, tubules and vesicles. It occupies 10% of the total cell volume. The cisternae are broad, flat, membrane-bound spaces arranged parallel to each other to form lamellae.

They are interconnected with each other. The tubules are 50 -100 A in diameter and appear as circles in sections. The vesicles or sacs appear as membrane-bound isolated globular cavities.

There are two morphological types of the ER. When some elements of ER are studded with small granules called ribosomes, it is called rough or granular ER. The other type is smooth or agranular, marked by the absence of these granules.

The strands of HR consist of biomembranes formed of lipoprotein and the space between them varies. SER in muscles is called sarcoplasmic reticulum and myeloid bodies in pigmented epithelial cells and retina of the eye. Ergnstoplusm is the basophilic region of cytoplasm containing RER. Desmotubiiles arc extensions of ER through plasmodesmata.

Cell The Unit Of Life NEET Notes

Functions. The ER and nuclear membrane arc are directly connected. The ER is connected with intercellular transport and cellular metabolism. ER also plays an important role in the synthesis of nuclear membranes during cell division. It also helps in protein synthesis, glycogen synthesis and storage, lipid synthesis and storage and formation of microbodies.

The ER gives additional mechanical support to the colloidal structure of cytoplasm and increases surface area for absorption.

Synthesis of steroids and hormones and the formation of visual pigments from vitamin A are also associated with ER. It synthesizes ascorbic acid and also takes part in detoxification of toxic chemicals.

NEET Biology Cell Unit Of Life Ribosomes

Ribosomes. Ribosomes are nucleo-protein protoplasmic subspherical structures without a covering membrane, negatively charged with a diameter of 150 to 250 A meant for a polypeptide or protein synthesis.

They were discovered by Palade and thus called “Palade particles”. These arc smallest ameinbranous cell organelles. Later these were named ribosomes. These are present in cytoplasm in the form of groups, called polysomes. Ribosomes are made up of ribonucleoprotein.

Ribosomes are of two basic types: 70S ribosomes in Bacteria and Blue-green algae, mitochondria and chloroplast, and 80S ribosomes in Eukaryotes. A 70 S ribosome has three molecules of r RNA 16 S, 5 S, 23 S, and 50 proteins mols.

80 S ribosome has four mols of rRNA (5 S, 5.8 S, 18 S and 28 S) and 80 mols of proteins. The 70S ribosomes are inactivated by the antibiotic Chloromycetin. The 80 S ribosomes are inactivated by cyclohexamide.

Ribosomes 80 S contain 40% and 60% RNA and protein respectively. Ribosomes are the seats of protein synthesis.

In mammalian mitochondria, ribosomes are of 55 S type. Proteins of all ribosomes are similar but it is the RNA which differs from ribosome to ribosome.

Prokaryotic And Eukaryotic Cells Differences NEET

Ergosomes or Polyribosomes (Rich 1963) are formed by protein synthesis.

• A tenfold increase in Mg2+ cone unites ribosomes to form Diamers. 70 S ribo some form 100 S while 80 S forms 120 S. If cone, is decreased by 10 folds, the ribosomes disassociate. Only unemployed ribosomes disassociate while active or those involved in protein synthesis do not disassociate.
• Lnke in 1976 proposed an asymmetrical model whereas Stefflar and Whittman, 1977, proposed a quasisymmetrical model for ribosomes.
• About 75 % of the ribosomes of cells remain bound to the C-face of the E.R. membrane through a glycoprotein ribophorin. In the case of He La cells the number of ribosomes is 15%.

• Proteins of all ribosomes are similar, however, it is r RNA that differs from one ribosome to another ribosome.
• Proteins synthesized on free ribosomes are used within the cell and those synthesized on bound ribosomes are used outside the cell.

Golgi Complex

Golgi Complex. These structures are also known as dictyosomes, gold some, idiosomes, Golgi apparatus or hypochondria, Dalton’s complex or Baker’s body.

In 1898, an Italian neurologist C. Golgi described certain previously unknown bodies in the cytoplasm of nerve cells of bam owls and cats using a special stain, Earlier the Golgi complex was thought to be present only in animal cells but recent research has shown that is present in plant cells.

Dalton and Felix observed them under TEM

Three distinct components are visible in the Golgi complex, they are

Tubularorflattened fluid-filled sacs or cisternae, each is membranous and parallel or concentrically with a convex (forming) surface towards the plasma membrane and the opposite concave surface is termed maturing surface,

Transition vesicles are small drop-like structures Secretory vesicles are present on the sides and the maturing face of Golgi.

Cell Organelles Structure And Functions NEET Biology

The elements of the Golgi complex may arise from ER, nuclear membrane or the pre-existing dictyosomes. It contains lipids, proteins and glycoproteins. Phosphatases, RUA, Phospholipids, ATP ases and S-nucleotidases are also present.

The metallic impregnation technique (osmium chloride silver salts)

NEET Biology Cell Unit Of Life Mitochondria

Mitochondria (Mito = thread, chondrion = granule) were discovered by Kolliker (1850) and the name mitochondria was given by Benda. Altman (1886) called them as ‘bioplasts’. He considered them as symbionts comparable to bacteria. In plants, mitochondria were discovered by Meaves (1904) in Nymphaea.

Mitochondria are also called Chondriosomes or Chondriomites plastochondria or filavermicules or bioplasts.

Mitochondria occur in the cytoplasm of plants and animal cells, the average length of the mitochondrion is 3 to 5 microns and the average diameter is 0.5 to 1.3 microns. They can be stained with Janus green B.

Using ultra vibrations and detergent actions, two membranes of mitochondria can be separated to study their structure. The mitochondrion without an outer membrane is called a mitoplast.

The mitochondrion is bounded by two membranes, the outer membrane and the inner membrane.

There are two chambers. The space between the two membranes is called the outer chamber and the space bounded by the inner membrane is called the inner chamber. The inner membrane forms mitochondrial cristae.

The enzymes of the Krebs cycle, flavo-proteins and cytochromes are present in mitochondria which are the centre of respiration. Mitochondria are also involved in oxidative phosphorylation and ATP synthesis. These are also called as ‘Power house’ of the cell.

Mitochondria arise from pre-existing mitochondria or ER. Mitochondria are semi-autonomous bodies. Nass, Nass and Afzeluis (1965) have shown the presence of DNA in mitochondria (MDNA). It constitutes 17c of the total DNA of the cell.

It is a double double-stranded, naked, granular, slim, long molecule with a higher G-C ratio. It is a circular molecule in most higher animal cells but is linear in several eukaryotic plant cells. Ribosomes arc of 70S type (55S ribosome in mitochondria of mammals) RNA and 70 types of enzymes are present.

Cell Organelles Structure And Functions NEET Biology

The mitochondria of whole cells are collectively called chondriosome or chondriomes. On cristae are present oxysomes or F0—Fj particles which are tennis racket-shaped bodies.

These particles were discovered by H.F. Moran and Chanre. These are also called as ETS particles as electron transport systems and ATP synthesis occurs on them. Besides this, mitochondria are concerned with lipid synthesis and elongation of fatty acids.

In prokaryotes where mitochondria are absent, the site for oxidative phosphorylation and electron transport, including dehydrogenases is the plasma membrane.

Single mitochondrion occurs in the case of:

• Microsterias Trypanosoma Chlorella.
• The maximum number is 5,00,000/cell in flight muscles.
• Meaves first to observe mitochondria in plants (Nymphaea).
• They can be stained by Gentian Violet and Janus green B.
• Cytochrome oxidase is present in the inner mitochondrial membrane.
• Mitochondria are rich in Mn. They are yellow due to riboflavin. They live for 5×10 days membrane only
• In all probability, the mitochondria arise from the nuclear envelope by evagination or by division of pre-existing mitochondria.
• Pyruvic acid enters mitochondria and is converted to Co. A in per mitochondrial space.
• ATP molecules are synthesised in the head.
• There are 5 chemical complexes. The first four constitute the electron transport system and the fifth transfers and conserves energy and (helps in) ATP synthesis.
• Mobile carriers = CoQ and Cyt C.
• Flavoproteins are located in Complex 1

NEET Biology Cell Unit Of Life Lysosomes

Lysosomes are diminutive vesicles encased by a singular membrane that contain hydrolytic enzymes in crystalline or semicrystalline forms.

• Christian de Duve discovered them. Lysosomes are present in nearly all animal cells, with the exception of mammalian red blood cells.
• Their diameters are 0.4 and 0.8 ™. These are lacking in plant cells; nevertheless, P. Matile (1964) has identified them in the fungus Neurospora.
• They are also referred to as ‘Suicidal bags’ or ‘Atom bombs’ due to their containment of hydrolytic enzymes.
• Lysosomes are most abundant in white blood cells, macrophages, osteoclasts, and similar cell types.
• Plant cells are devoid of lysosomes, with the exceptions of Neurospora, maize root tips, yeast, and the seeds of peas and cotton. Lysosomes originate from the M face of the Golgi apparatus.
• Lysosomes execute various duties, including the digestion of food, the phagocytosis of foreign particles, involvement in metamorphosis, scavenging, supplying enzymes for the degradation of egg membranes, and facilitating the disintegration of ageing and dead cells.
• Lysosomes eliminate toxins through engulfment and appear to be crucial for cellular division.
• Additionally, they have an inherent mechanism that allows a cell to adapt.

Lysosomes exist in more than one morphological form, hence show polymorphism and they are of the following four types:

• Primary lysosomes (also known as original lysosomes storage granules or inactive lysosomes).
• Secondary lysosomes (heterolysosome or phagolysosome heterophagic vacuoles or digestive vacuoles).
• Autophagic vacuoles (autolysosomes or autolysosomes).
• Residual bodies (telo lysosomes dense bodies or tertiary lysosomes).

NEET Biology Cell Unit Of Life Plastids

Plastids. Plastids (Haeckel, 1866) are semi-autonomous organelles having DNA and a double membrane; envelope which synthesizes or stores different types of organic compounds.

The chloroplasts are green plastids (Schimper 1833) which take part in the synthesis of organic food from inorganic raw materials in the presence of radiant energy or light and the process is termed photosynthesis.

Eukaryotic plants contain a heterogeneous group of cell organelles called plastids which vary in morphology and function, some plastids are colourless, called leucoplasts. They store reserve materials, such as starch, proteins and lipids.

Green plastids are called chloroplasts which contain chlorophyll. Still others the chromoplasts. contain carotenoids which are brilliant red or yellow.

All three plastids differentiate from small spherical amoeboid structures 0.4 to 0.9 um in diameter called proplastids. Plastids are the largest cell organelles.

The increasing order of plastid size is as follows:

Chloroplast → chromoplast → elaioplast → aleuroplast → amyloplasts.

The distribution of pigment systems are coupling factor in thylakoid membranes. The chloroplasts are usually discoidal or lens-shaped double membrane organelles.

They are made up of chlorophyll a and b carotenoids, lipids, proteins and nucleic acid. DNA in chloroplast was reported by Ris and Plaut.

The chloroplasts are ‘autonomous bodies and. thus, are also called “cells within cell organelle.” The membrane-bound matrix of chloroplast is called stroma where dark reaction or Calvin cycle of photosynthesis takes place. In the stroma are present thylakoids which form grana acting as site of light reaction where assimilatory power (ATP 4- NADPH,) are synthesized.

Fluid Mosaic Model Of Cell Membrane NEET Study Material

The smallest and most functional unit of chloroplast is called the photosynthetic unit or Quantosome. The term Quantosome was given by Park and Biggins (1964).

Each Quantosome consists of 250 molecules ofchlorophyll. The molecular weight quantosome is 2 x 106.

The size ofquantosome is length = 1 80 A width = 155 A and thickness = 100 A. It is considered that chloroplasts might have originated from a symbiotic relationship between an autotrophic microorganism capable of transforming energy from light and a heterotrophic cell.

• Thylakoid membrane consists of 2 photosystem complexes namely photosystem 1 and photosystem 2 their reaction centres being P-700 and P-680.
• LHCP = Light-harvesting complex protein. It is present in the thylakoid membrane and is photochemically inactive.
• Plastids are called intracellular parasites and a symbiont hypothesis is used to explain them.
• The plastidial system carrying genetic information is called the plastidome.
• Chloroplast of higher plants chemically is composed of
• Protein: 33-35%
• Chlorophyll: 9%
• Lipids: 20-30%
• Carotenoids: 4-5%
• Nucleic acids : 3-4%, traces of Vit K and A, Ribosomes 70
• Protein lipid ratio in the chloroplast is 40: 30
• No. of grana in chloroplast ranges from 10-100
• C4 plants have dimorphic chloroplasts.
• Chloroplasts move in the cell due to cyclosis.
• Chloroplast is more important than chlorophyll as carotenoids in chloroplast protect chlorophyll from photo-oxidation.
• Chloroplasts with nitrogen-fixing genes are called nitroplasts.
• The three kinds of plastids are interconvertible

Classification based on pigmentation.

1. Chromoplast: coloured plastids
2. Chloroplast: ‘Chlorophyll a & b c.g. green algae
3. Phaeoplast: Fucoxanthin Example brown algae, diatoms.
4. Rhodoplast: phycoerythrin Example red algae
5. Blue-green chromoplast, ‘phycocyanin Example Blue-green. Algae
6. Leucoplast colourless plastids
7. Amyloplast: Starch storing
8. Elaioplast (Oleasome): Fats storing.
9. Aleuroplast (Proteinoplasts) : protein storing.

Shapes

• The chlorophyll in grana is surrounded by 2 protein layers (Y-shaped) in between the protein and chlorophyll there occurs lipid chlorophyll.
• Leaf palisade mesophyll cells of higher plants contain 20-40 chloroplasts.
• Single thylakoid occurs in the granum of Rhodophyceae.
• Quantosome is believed to have (160 a + 70 b) chlorophyll and 50 carotenoid molecules.
• Chloroplasts which lack granum are often described as agranal or Kranz type.

NEET Biology Cell Unit Of Life Microbodies

Peroxisomes (Uricosomes)

These are single membrane-bound vesicles with a size ranging from 0.5 to lim. They were discovered by Tolbert and the term peroxisome was coined by de Duve (1969) for those microbodies which are rich in enzymes peroxidase classes and catalases and produce hydrogen peroxide during their degrading activity.

These vesicles contain fine, granular substances that may condense to form a central core or nucleoid.

The peroxisomes without nucleoids are called micro-peroxisomes. The enzymes present are:

• Uric acid oxidase
• α – amino acid oxidase.
• α – Hydro xylic acid oxidase.
• β Hydroxylic acid oxidase.
• NADH-glyoxalate reductase.
• NADH-isocitrate dehydrogenase.
• Catalase.
• Peroxidase.
• Peroxisomes generally arise from ER. These bodies take part in H202 metabolism and in green plants, they carry out photorespiration.

Sphaerosomes

Hanstein (1880) observed small highly refractive bodies of a denser substance in the cytoplasm of plant cells and later Danglard termed them sphaerosomes. They are microbodies which take part in the storage and synthesis of fats.

They were first discovered by Perner in 1953. Sphaerosomes are small spherical and refractile vesicles which are 0.5— 1.0 mm in diameter.

They arise from the ER and are surrounded by a single membrane. 98% of a phagosome is fat. Proteins constitute the remaining 2%. Some proteins are probably enzymatic and take part in the synthesis of fats.

Fluid Mosaic Model Of Cell Membrane NEET Study Material

Because of the presence of fat, phagosomes can be seen under light microscope after staining the cells with Sudan dyes and osmium tetraoxide. Sphaerosomes occur abundantly in the endospermic cells of oil seeds.

Sphaerosomes of some tissues Example tobacco endosperm, and maize root tips contain hydrolytic enzymes. Therefore, they are considered to have lysosomic activity.

Glyoxysomes

• They are microbodies which contain enzymes [5-oxidation of fatty acids and glyoxalate pathway. These microbodies were discovered by Breidenback and Beevers (1967) from the extracts of the endosperm of germinating castor beans.
• They are also present in the cells of some fungi. Like other microbodies, glyoxysomes have a single covering membrane and a matrix with a crystalloid core.
• The matrix contains enzymes for (3-oxidation of fatty acids to produce Acetyl CoA. The latter is metabolised in the glyoxylate cycle to produce carbohydrates.

Lomasomes

They were discovered by Moore and McAear (1961) and are often referred to as border bodies. These bodies are present between the cell wall and cell membrane of both lower and higher plants. They play a role in secretion, increasing the surface area for the diffusion of substances involved in cell wall formation or breakdown in membrane proliferation and endocytosis.

Transosoines

• These bodies were discovered by Press (1964) and are so far known to occur only in the ovarian follicles of birds.
• These are circular and consist of triple-bonded envelopes with several ribosome-like granules attached by short stalks to the innermost band. It is believed that they have a role with the developing yolk granules but their exact function is not known.

NEET Biology Cell Unit Of Life Centrioles, Cilia And Flagella

Centrioles. They were first observed by Van Benden in animal cells. They are minute microtubular rods which can help to form their duplicates without having DNA and membranous covering.

Usually, two centrioles called diplosomes are present near the nucleus of all eukaryotic animal cells, primitive plants and all eukaryotic where flagellate structures and all eukaryotic plants where flagellate structures are present.

Mature centrioles are 0.2 lim in diameter and vary in length from 0.2 to 0.5 pm. A pair of centrioles surrounded by a clear area of cytoplasm, the centrosphere, is called a centrosome. Each centriole consists of nine sets of microtubules arranged circularly.

These tubules are equally spaced. Each microtubule is a triplet (diameter 250 A) of microtubules or subfibres embedded in a matrix designated as A, B, C and from inner to outer subfibre. Each subfibre is made up of 11—13 protofilaments of tubulin. The A-subfibre of a triplet is attached to the C-subfibre of the adjacent triplet by strands called linkers.

The central hub is (20 A in diameter), and from it arises 9 proteinaceous connectives called spokes, one towards subfibre.

Mitochondria And Chloroplasts Roles NEET Exam Preparation

A thickening ‘X’ is present at the outer end of each spoke and another Y is present between the two X thickening and are connected.

There are dense, amorphous, protoplasmic structures called macule satellites or pericentriolar structures on the surface of centrioles. Centrioles are locomotory structures and their role in cell division is acquired secondarily.

Cilia and flagella

• (Studied by Englemann and confirmed by Jensen 1881) are hair-like protoplasmic processes of cells capable of undergoing movements and thus create a current jn -any fluid for locomotion and passage substances.
• Both cilia and flagella have the same basic structure and differ in number, size and type of movement.
• Chemically, they are mainly formed of protein and lipids, traces of carbohydrates and nucleotides are also present. Tubulin protein occurs in peripheral fibrils while dynein is found in the side arms of A-subfibrils spokes and central fibrils.

Structure

• The cilia and flagella are essentially of the same structure and both arise from basal bodies. Cilium is surrounded by a membranous covering which is an extension of the plasma membrane. Both the membranes are separated by a space of 90 A.
• The space between the limiting membranes of the cilium is filled with a matrix. In the matrix is embedded axial fibril complex.
• The central axial filament complex consists of eleven microtubules arranged in two radii; out ofthese nine are double and are situated at the periphery and two single microtubules are placed in the centre.
• Each of the nine outer tubules is 360 A in diameter and composed of two subunits. A sheath surrounds the central fibrils. The outer fibrils bear a pair of arms Radial lamellae, each with a thin secondary fibril, occur between central and outer fibrils.
• Central singlet fibres are made up of a protein dynein with ATP-ase activity. Outer double fibres are made up of tubulin protein while A-B linkers are composed of protein nexin.

NEET Biology Cell Unit Of Life Cytoskelclal Supporting Structures

• Intermediate filaments are long, unbranched having structure intermediate between microtubules and microfilaments and consist of a head, central rod and tail. First discovered in muscle cells (1968).
• Microtubules earlier called neurotubules were first discovered by Sabatini, Bensch and Barnette (1963).
• Microtubules and microfilaments form a complex structural framework of the cell. They are concerned with movement by or within the cell. They also can maintain the shape of the cell.
• Microfilaments are long, thin, cylindrical rods composed of actin (protein).
• Microfilaments are 6-10 nm in diameter and contract with the help of myosin.
• Microfilaments may extend into the cytoplasmic core of microvilli.
• Microfilaments are responsible for movement of the plasma membrane during cell mobility and endocytosis; contraction of muscle fibres and movement of microvilli.
• Microtubules are elongated unbranched, cylindrical tubes of about 25 nm in diameter.
• Each tubule encloses a light central core of 15 nm diameter. The microtubule’s wall is made up of 13 longitudinal filaments, each is a polymer chain of tubulin protein.
• Microtubules occur singly or in bundles in cytoplasm radiating from the controls to the peripheral parts.
• These form the skeleton of cilia and flagella and spindle during cell division helping in the movement of chromosomes. They can be broken down and reassembled in another part of the cell.

NEET Biology Cell Unit Of Life Interphase Nucleus

The nucleus of the cell which is not in the process of division is called interphase nucleus.

Robert Brown first noticed the largest organelle, the nucleus. It is present in all eukaryotic cells except RBC. Cells usually have one nucleus (mononucleate), but some cells may be binucleate or polynucleate.

It may be placed in the centre or one side of the cell. It is mostly spherical or oval in shape or it may be elongated or even lobulated. The size of the nucleus depends upon its proteins and DNA contents.

The cytoplasmic and nuclear masses remain in the state of equilibrium known as endoplasmic or kanophismic index (NP or KPL)

Nuclear envelope. The nucleus is bounded externally by a double membrane, the nuclear membrane, which beats sub-microscopic pores and through these pores it is in continuation with the membranes of the endoplasmic reticulum.

The space between the two nuclear membranes is called the perinuclear space. Each membrane is 75 A in diameter and perinuclear space is 150-350 A wide.

In structure and function, the nuclear membrane resembles the cell membrane. It disappears during cell division and is redeveloped tram the membrane of the endoplasmic reticulum. Internally, the nucleus is filled with a viscous fluid, the nuclear sap. nucleoplasm or karyolymph. It is rich in protein and contains nucleic acid.

Nucleolus. (PI. Nucleoli Fontana 1784, discovered which was described by Wagner (1840) and Bowman (1S40) provided the present name. Nucleolus is an irregularly shaped often dense and compact body. It consists of protein and RNA. The patient forms SOT of the dry weight of the nucleolus. The nucleolus performs three functions, synthesis of proteins.

Mitochondria And Chloroplasts Roles NEET Exam Preparation

synthesis of ribosomal RNA and transfer of genetic information from the nucleus to the cytoplasm. It is interesting to note that the nucleolus disappears during cell division. Chromatin material or network is a granular mass which lies in the nucleoplasm.

The chromatin with fine threads is called euchromatin. The chromatin material consists of DNA. RNA. histone and acidic protein. During cell division, the chromatin material organizes itself and becomes distinct as chromosomes.

Differences Between Euchromatin And Heterochromatin

Nuclear functions. Robert Brown (1831) discovered the nucleus which was later mentioned as store storehouse of heredity information. Van Benedan and Hertwig demonstrated the role of the nucleus during the fusion of male and female gametes.

Boveri (1889) experimented with sea urchin eggs and established that survival, growth and reproduction are controlled by the nucleus.

Hammerling’s (1913) grafting experiment with Acetabularia Mediterranean proved that morphology is governed by the nucleus.

Hofmeister observed chromatin threads during cell division. Sutton and Boveri observed parallel behaviour between chromosomes and genetic characters and proposed the chromosome theory of heredity.

The DNA constituents of the nucleus act as the chemical basis of genetics. Structure of chromosome.

The chromatin network undergoes condensation, and coiling and is transformed into a definite rod-shaped structure of the chromosome. The chromosomes were discovered first by Hofmeister and the word chromosome was given by Waldeyer (1888).

A typical chromosome has the following parts:

Pellicle. It is the outermost covering membrane chromosome. However, Ris (1945) denies the presence of pellicles.

Matrix. It is the ground substance of chromosomes and contains a chromatin network.

Chromonema. There are two spirally coiled threads in the matrix, known as chromonemata. They are seen throughout the length of the chromosome. Each chromonema is 800 A in thickness and consists of one molecule.

Chromoniercs. These are dot-like or hcad-like structures of chromonema which have coiled up in specific ways to form complex and dense chromatin, the chroinomcres.

Mitochondria And Chloroplasts Roles NEET Exam Preparation

Centromere. It is situated in the region of primary constriction. In this region, the two chromonema join to form one.

The position of the centromere helps in the identification of chromosomes. According to the position of the centromere the chromosomes are of four types: metacentric, submetacentric, acrocentric and telocentric.

According to the number and presence or absence of centromeres, chromosomes arc of the following types:

Acentric (without centromere), monocentric, dicentric and polycentric with one, two or many centromeres.

Secondary Constriction. This constriction may be present in one or both arms of the chromosomes. This is the place where a nucleolus appears and disappears during the cell cycle. Thus it is also known as the nucleolar organizing region.

Satellite. The distal spherical part of chromosome above sec. constriction is known as a satellite. The chromosomes having satellite arc are known as SAT-chromosomes where SAT stands for Sine Acid Thymunucleinico.

Telomere. Each chromosome has polarity. Its terminal ends are physiologically different from the rest of the chromosomes and are known as telomeres. They avoid sticking of chromosomes in the nucleus. If by X-rays these ends arc broken, then one chromosome will stick to another chromosome.

In chromosomes, DNA and histones arc bonded to form dcoxyri bonuclcoprotcin. The most accepted model for the arrangement of DNA and histone protein is the nucleosome or sole noid model (Woodcock).

The term nucleosome was given by. Outlet ( 1 975). To accommodate the nucleosome model for DNA, Crick and Watson proposed the Kinky helix model for DNA. A nucleosome is a repeating unit of chromatin (125 nm is diameter = 200 base pairs + 2 molecules each of H2A, H2B, H3 and H4)

Lampbrusli Chromosomes. Such chromosomes are found in the oocytes of amphibians and appear like a brush which was used in the olden times to clean street lamps. That is why, they are known as lampbrush chromosomes.

A lampbrush chromosome consists of a central main axis made up of DNA whereas the matrix which consists of RNA and protein is present in the form of a loop of the main axis. The loops lie opposite to each other.

Endoplasmic Reticulum Types And Functions NEET

Each loop consists of an axial fibre which is covered with a matrix. When it is treated with ribonucleases (an enzyme which breaks down DNA) it is broken down indicating that it consists of DNA.

When it is treated with ribonucleic (an enzyme which breaks down RNA), trypsin and pepsin the matrix of the loop is removed. From that, it can be concluded that the matrix is composed of RNA and protein whereas the axial fibre of DNA.

Polytene Chromosomes. They were first observed by Italbiani (1881) in the salivary gland of Chirommous and hence sometimes are also known as salivary gland chromosomes.

They are also found in Drosophila. In Chironomus, usually, one somatic cell consists of 8 polytene chromosomes. They measure 1000 times larger than normal chromosomes. They are 2,000 Im in length.

A polytene chromosome consists of several parallel strands, chromonema. The coils containing polytene chromosomes continue to grow without undergoing mitosis. One chromosome may have as many as 1024 chromonemata. All strands are genetically identical.

• m-chromosomes. Minute-sized (less than 0.5 mm) chromosomes are found in many bryophytes. and insects.
• Chemically, Chromosomc is formed of 40% DNA, 50% histones, 1.5% RNA, etc. H, H2A and Hyn proteins are lysine-rich (2 is very lysine-rich) while H3 and H4 are arginine >ric)i polypeptide chains.
• Satellite is also called Trabant.
• NOR constitutes 03% of total nuclear DNA. NOR is also called secondary constriction I.
• Muller (1938). Coined the term telomeres.
• Vejdovsky (1912). Coined the term chromonema.
• Du Praw : (1966). Proposed uncinematic folded fibre model of the chromosome.
• Finch and Klug (1976). Proposed solenoid model. It states that DNA is associated with histone proteins to form a series of beads called nucleosomes.
• Nucleosomes: Fundamental packing unit of chromonema.

NEET Biology Cell Unit Of Life Cell Inclusions

Reserve food. It may be in the form of starch grains (Example in potato-tuber cells) or glycogen granules (Example in liver and muscle cells of animals), protein granules (Example in aleuroplasts of the endosperm of maize seed), or oil droplets (Example in adipocytes of fat bodies; endospermic cells of castor and coconut and in cotyledon cells of groundnut and mustard seeds).

Gases. These include O2, CO2, N2 etc.

Inorganic crystals. These include crystals of calcium salts and silica. Silica is generally found in the epidermal cells of grasses. Crystals of calcium carbonate, called cystoliths, are found in the epidermal cells of Mimordica (Kerala), while crystals of calcium oxalate are called raphides and are found in the epidermal cells of Eichhomia (water hyacinth). Hyaloplasm also contains organic acids like tartaric acid (In tamarind), citric acid (citrus fruits) and malic acid (as in apples).

Excretory/Secretory Products. They include mucus, tannins, resins, gums, alkaloids, latex, etc.

Latex. It is a crystallo-colloid fluid secreted by latex tubes or Iaticifers of two types, latex cells (non-articulated Iaticifers, Example Banyan, Calotropis, Oleander) and latex vessels (articulated Iaticifers, Example Poppy, Rubber plant, Sonchus). Latex can be watery (For example Banana), milky (For example Banyan) or coloured (For example Poppy).

The latex of Hevea brasiliensis yields rubber, that of Poppy forms opium while the latex of Papaya contains the protein-digesting enzyme papain,

Gums. They are degradation products of cell walls, for example, gum Arabic (Acacia Senegal).

Gum-Resin. It is mixture of gum and resin, Example root of Ferula asafoetida (asafoetida).

Resins. They are acidic oxidation products of essential oils which are insoluble in water but soluble in alcohol/ turpentine. An example of hard resin is shellac. Pine resin and Canada Balsam are oleo-resins (resins with associated essential oils).

Endoplasmic Reticulum Types And Functions NEET

Tannins. They are astringent, acidic, phenolic compounds, related to glucosides, found in leaves (For example Tea), bark (For example Acacia nilotica, Walnut or Juglans regia) fruit (For example Caesalpinia, Betel Nut), Dyes related to tannins are cutch (heartwood of Acacia catechu), and haematoxylin (heartwood of Haematoxylon).

Alkaloids. They are bitter nitrogenous by-products, often poisonous and with medicinal properties, Example quinine (bark of Cinchona officinalis), atropine (leaves and tops of Atropa belladonna), nicotine (leaves of Nicotiana tabacum (tobacco), morphine (latex of Papaver somniferum (poppy), reserpine (roots of Rauwolfia serpentina), colchicine (corms of Colchicum autumnale), thein (Tea leaves),

Glucosides present is crucifers. They are aromatic compounds having glucose/carbohydrates, for example, saponin, digitoxin, digitalin, and amygdalin. Many of them are medicinal, (viii) Essential Oils. They are volatile aromatic oils secreted by special glands, Example Lavender, Rosemary oil, Menthol, Eucalyptus oil,

Nectar. It is the sugary secretion of parts of flowers to attract insects and other animals for pollination. Nectar contains glucose,’ fructose and sucrose.

Pigments. These are found in special cells, called chromatophores, present in the skin (dermis) of vertebrates (fishes, amphibians and reptiles).

The chromatophores are of two types: melanophores have brown or black pigment, and lipophores contain red, yellow and orange pigments. Birds and mammals have a pigment in their feathers and hair. In the human skin, the pigment-containing cells occur in the deeper epidermal cells

• Prokaryotic cells are represented by bacteria, blue-green, algae, mycoplasma or PPLO, spirochaete and rickettsiae generally smaller than eukaryotic cells but multiply more rapidly.
• The bacterial flagellum is formed of filament, hook and basal body which is a hollow rigid, cylindrical filament longest (1-70 nm), formed of flagellin protein.
• The basal body of the bacterial flagellum is a complex part of the flagellum, consisting of four and two rings connected to the central rod in Gram-ve and Gram+ve bacteria respectively.
• The filament, hook and basal body are arranged in such a manner to permit the filament to rotate by 360° rather than undulating back and forth like a whip. In the plasma membrane of eukaryotic cells sterol molecules are more rigid than phospholipids and therefore the presence of sterol confers stability on each eukaryotic membrane.
• Three principal types of protein filament-microfilaments (7nm), microtubules (25nm) and intermediate filaments (8-10nm) are cytoskeletal elements which allow the eu¬ karyotic cell to adopt a variety of shapes and carry out directed movements.
• In Golgi bodies, materials are transported from the cis to the trans face by vesicles that keep budding off from the cisternal edge to the next cell and so on.
• The sequence of the size of the organelles is as follows:
• Lysosome(0-2-0-8pm) <Sphaerosome (0-5-1 -0pm) < Per peroxisome (0-5- M pm)< Ribosome (l-5-2-0pm)
• Pinosomes and phagosomes are collectively known as endosomes.
• The vacuoles of plant cells are bounded by a single semipermeable membrane called tonoplast, whereas the vacuoles, of animal cells are by, a lipoprotein membrane.
• Vacuoles are of four types depending upon function t. sap vacuoles, contractile vacuoles, food vacuoles and air, rapidly.
• vacuoles/ The proper folding of proteins following synthesis is assisted by a special protein called chaperones.
• Mitochondria can be seen in inactive or orthodox state and active or condensed state.
• Both mitochondrial (mt DNA) and chloroplast DNA (cp DNA) containing limited genetic information are circular although cp DNA is much bigger than mt DNA
• The amount of DNA is low in a chloroplast i.e. 10-15 to 10y grams per chloroplast or 0-03% of its dry weight.
• Cilia and flagella having a 9+2 arrangement are associated with the motility of cells.
• Karyotype. The arrangement of chromosomes in terms of their relative size, form and number is called karyotype. It consists of the arm ratio and position of the centromere also. It is characteristic of a species.
• Karyotype preparation can be done by either banding technique or fluorescence in situ hybridisation (FISH) and multicolour fluorescence in situ hybridisation (FISH) or Flow cytometry.
• Idiogram. A pencil sketch or photograph of the karyotype is called idiogram.
• Human Karyotype. Somatic cells contain a total of 46 chromosomes (Tijio and Levan 1956) or 23 pairs.
• Out of these 22 pairs are autosomes, one pair of sex chromosomes XX in females (homomorphic) and XY in males (heteromorphic).

Quanta to memory

• The term ‘cell’’ coined by Hooke (1665), is; a misnomer as the cell is not a hollow structure.
• Cytoplasm coagulates at temperatures above 60° C.
• Swammerdam was the first to describe the cell (RBC of frog).
• Largest cell—Egg of ostrich (6 inches in diameter with shell and 3″ without shell.)
• The nerve cell is the longest in the human body. The smallest cell (Mycoplasma gallisepticum—PPLO) measures 0.1 to 0.3 pm. Unicellular eukaryotes are 1 to 1000. pip in size. The size of human RBC is 7-8 pm.
• Cells of multicellular eukaryotes are 5 to 1000 pm in size.
• Fibre of Boehmeria (longest plant cell is 55 cm in size).
• PPLO (Mycoplasma Lauderhill) are also called “Jokers
  of plant kingdom.
• Transosome organelles are bounded by triple membranes.
• Organelles without membranes are ribosomes, centrioles,
  microfilaments and microtubules
• In human beings, cells of the kidney are the smallest and of nerve fibres largest.
• The size of human RBC is 7-8 pm.
• Cells of multicellular eukaryotes is 5 to 1000 pm in
  size.
• Fibre ofBoehmeria (longest plant cell is 55 cm in size). PPLO (Mycoplasma laiderwili) are also called “Jokers of the plant kingdom.”
• Transosome organelles are bounded by triple membranes. Organelles without membrane are ribosomes, centrioles, microfilaments and microtubules.
• In human beings, the cells of the kidney are the smallest and of nerve fibre largest.
• Intracellular compartments in cells help in the efficient functioning of cells.
• A pyrenoid is a proteinaceous body around which starch is stored in green algae.
• Protochlorophyll differs from chlorophyll in lacking 2 hydrogen atoms in two of its pyrrole units.
• Microtubules are involved in cell division.
• Two genome types are present in typical green plants.
• Basophilic ergastroplasm indicates the presence of ribosomes.
• Chromosomes are stained with acetocarmine processing or Acid Fuschia.
• Bioblast = Mitochondrion = Bioplast = unit of protoplasm capable of reproducing itself.
• The cell wall is capable of growth and is involved in many enzymatic activities, so is now considered as a living structure.
• A ripened fruit becomes soft because the pectates of the middle lamella solubilize on ripening.
• Myeloid bodies (granules at the base of retinal pigment cells) and Nissl granules (in the cyton of neurons) are RER (ER with ribosomes).
• Svedberg Unit (S). It is the rate of sedimentation or velocity of sedimenting the particles per unit of gravitational force, or lx 10-13 cm /sec/dyne/gm.
• The largest component of the cell is the nucleus while the smallest component is the microfilament.
• The largest cell organelle is the mitochondrion in animal cells and plastid in plant cells while the smallest cell organelle is the ribosome.
• The darkly staining property of chromatin is called heteropykinosis.
• Mitoribosomes of mammals have a sedimentation coefficient of 55 S.
• Smallest Human Cell. Erythrocytes with a diameter of 6-8 pm. Blood platelets are still smaller (2-3 pm in diameter) but they are considered to be cell fragments instead of cells themselves. (Malarial sporozoite is 2 pm in length).
• Coconut milk is widely used in tissue culture as it is rich in a kind of growth hormone named cytokinin.
• Callus and Cancer both are undifferentiated masses of cells.
• But calluses get differentiated into root and shoot by auxins and cytokinins in tissue culture and cancer cells fail to differentiate in tissue culture.
• The explant is an excised plant part used in tissue culture to
  raise Callus.
• Animal Cloning. Animal cells are totipotent like plant cells but there is difficulty in their dedifferentiation and later differentiation.
• Animal cloning has become possible by inserting the nucleus of a somatic cell into an enucleated egg and allowing the latter to develop into the uterus of a female. The first successfully cloned animal is Dolly, a sheep (1996—1997)

NEET Biology Cell Unit Of Lift And Structural Organization MCQs

Question 1. The part/parts of a cell that can be seen with an electron microscope, but never with a light microscope is/are the:

1. Nucleus
2. Golgi bodies
3. Chloroplasts
4. The membrane separates the nucleus from the cytoplasm.

Answer: 4. Membrane separating the nucleus from the cytoplasm.

Question 2. Fundamentally a dead cell differs from a living cell because:

1. It has become separated from other cells
2. Its vital forces have been destroyed
3. A change in its surrounding environment has occurred
4. A change in its specific organization has occurred.

Answer: 2. A change in its surrounding environment has occurred

Question 3. Plant cell differs from animal cells by :

1. Cell wall absent in animal cell but chloroplast present
2. Cell wall and chloroplast absent in animal cell
3. Vacuoles only a few and that too contractile are present in plant cell
4. Cell walls are present in an animal cells.

Answer: 2. Cell wall and chloroplast absent in animal cell

Read and Learn More NEET Biology Multiple Choice Question and Answers

Question 4. The organic molecules present in traces in living cells can be detected and isolated by:

1. Centrifugation
2. Tracer technique
3. Chromatography
4. Microscopy.

Answer: 3. Chromatography

Cell The Unit of Life Botany NEET MCQQuestion 5. The cell theory was proposed by :

1. Robert Hooke
2. Leuwenhoek
3. Schleiden and schwann
4. Purkinje.

Answer: 3. Schleiden and schwann

Question 6. 1 A is equal to:

1. 10 8 Cm
2. 10Acm
3. 10-6 Cm
4. 10 3 Cm.

Answer: 1. 10 8 Cm

Question 7. Which of the following sets resemble in their basic structure and function:

1. Centrioles, cilia and flagella
2. DNA, MRNA And TRNA
3. Er, Golgi complex and lysosome
4. Leucoplast, chloroplast and chromoplasts.

Answer: 1. Centrioles, cilia and flagella

Question 8. How many membranes comprise the nuclear envelope?

1. One
2. Two
3. Three
4. None.

Answer: 2. Two

Question 9. Which of the following organelles regularly moves from the nucleus to the cytoplasm?

1. Glycogen
2. Cholesterol
3. RNA
4. DNA.

Answer: 3. RNA

Cell The Unit of Life Botany NEET MCQ Question 10. Which of the following cellular organelles breaks down complex macromolecules such as polysaccharides and proteins?

1. Golgi complex
2. Lysosome
3. Mitochondria
4. Rough endoplasmic reticulum.

Answer: 2. Lysosome

Question 11. The fuel gen reaction of dna is due to :

1. Aldehyde produced by acid hydrolysis
2. Removal of RNA but not dna
3. Phosphoric acid, carbohydrates and nitrogen bases
4. Phosphoric acid.

Answer: 1. Aldehyde produced by acid hydrolysis

Question 12. Which one of the following does not lose living nature even after crystallization?

1. Protista
2. Bacteria
3. Viruses
4. Parazoa.

Answer: 3. Viruses

Question 13. In prokaryotic cells, the enzymes involved in the oxidation of metabolites is associated with :

1. Nucleoid
2. Plasma membrane
3. Ribosomes
4. Plasmosome.

Answer: 2. Plasma membrane

Question 14. Which of the following is an exception to cell theory?

1. Bacteria
2. Protozoans
3. Protista
4. Viruses.

Answer: 2. Protozoans

Cell The Unit Of Life MCQ For NEET Biology With Answers Question 15. Which of the following relationships between cell structure and their respective function is not correct?

1. Cell wall – support, protection
2. Cilia – site for diffusion
3. Chromosome – carrier of heredity material
4. Mitochondria – a powerhouse of cell1.

Answer: 4. Mitochondria – powerhouse of cel1.

Question 16. A human egg is very large compared to a human sperm. Most of this size differential is due to the difference in their:

1. Nucleus
2. Membranes
3. Cytoplasm
4. Both 1 and 3.

Answer: 3. Cytoplasm

Question 17. The cortex of the human brain may consist of :

1. Six billion, two hundred million cells
2. Seven billion, two hundred million cells
3. Eight billion, two hundred million cells
4. Nine billion, two hundred million cells.

Answer: 2. Seven billion, two hundred million cells

Question 18. The human body weighs about 50 kg. May consist of:

1. 25 X 1015 cells
2. 50 X 101s cells
3. 100 X 101s cells
4. 150 X 101s cells.

Answer: 4. 150 X 101s cells.

Question 19. Nucleoli are rich in :

1. Ribose nucleic acid
2. Deoxyribose nucleic acid
3. Proteins and RNA
4. Carbohydrates.

Answer: 3. Proteins and RNA

Question 20. Which of the following phenomena is not found in viruses in the host cell?

1. Replication
2. Production of energy
3. Mutation
4. None of the above.

Answer: 2. Production of energy

Question 21. The correct order of sedimentation of subcellular structures during differential centrifugation is as follows:

1. Lysosome -+ mitochondria -+ nucleus -l ribosome
2. Mitochondria-+ nucleus -+ lysosome -+ ribosome
3. Nucleus -+ mitochondria->lysosome + ribosome
4. Lysosome -+ ribosome-+ mitochondria –> nucleus.

Answer: 3. Nucleus -+ mitochondria->lysosome + ribosome

Cell The Unit Of Life MCQ For NEET Biology With Answers Question 22. Which of the following represents the correct sequence of relative sizes in descending order?

1. Cell, nucleus, chromosome, water molecule, oxygen atom
2. Cell, nucleus, water molecule, oxygen atom, chromosome
3. Chromosome, cell, nucleus, water molecule, an oxygen atom
4. Cell, nucleus, water molecule, chromosome, oxygen atom.

Answer: 1. Cell, nucleus, chromosome, water molecule, oxygen atom.

Question 23. The activities of all living cells are controlled by :

1. Chloroplasts
2. Auxins
3. Nucleus
4. Tonoplast.

Answer: 3. Nucleus

Question 24. Leaf pigments are separated from a mixture by :

1. Spectrophotometry
2. Autoradiography
3. Chromatography
4. Microcinematography.

Answer: 3. Chromatography

Question 25. Which of the following sets of cell organelles contains dna?

1. Mitochondria, ribosomes and chloroplasts
2. Nucleus, ribosomes and chloroplasts
3. Nucleus, ribosomes and mitochondria
4. Nucleus, mitochondria and chloroplasts.

Answer: 4. Nucleus, mitochondria and chloroplasts.

Question 26. Leaving aside water, which of the following constitutes the bulk of an active living cell?

1. Ribose nucleic acid
2. Deoxyribose nucleic acid
3. Proteins
4. Carbohydrates.

Answer: 3. Proteins

Cell The Unit Of Life MCQ For NEET Biology With Answers Question 27. Which one of the following is incorrect?

1. All cells do not contain a true nucleus
2. All living plant cells contain chlorophyll
3. Cell rivals are generally made up of cellulose
4. Respiration occurs in mitochondria.

Answer: 2. All living plant cells contain chlorophyll

Question 28. The endoplasmic reticulum often contains :

1. Ribosomes
2. Golgi bodies
3. Centrioles
4. Lysosomes.

Answer: 1. Ribosomes

Question 29. The fine network of membranes distributed extensively throughout the cytoplasm in a cell is referred to as:

1. Golgi bodies
2. Peroxisome
3. Lysosome
4. Endoplasmic reticulum.

Answer: 4. Endoplasmic reticulum.

Question 30. The endoplasmic reticulum occurs in the form of:

1. Cisternae only
2. Vesicles only
3. Tubules only
4. All the above.

Answer: 4. All the above.

Question 31. The endoplasmic reticulum in the cells of adipose tissue is in the form of:

1. Vacuoles
2. Sacs
3. Tubules
4. All the above.

Answer: 1. Vacuoles

Cell The Unit Of Life MCQ For NEET Biology With Answers Question 32. When the region of the endoplasmic reticulum is studded with ribosomes on the outer surface of the cisternae. It is called:

1. Sarcoplasmic reticulum
2. Smooth endoplasmic reticulum
3. Granular endoplasmic reticulum
4. None of the above.

Answer: 3. Granular endoplasmic reticulum

Question 33. The principal site of the synthesis of ribosomal RNA is the :

1. Mitochondria
2. Golgi bodies
3. Nucleolus
4. Lysosomes.

Answer: 3. Nucleolus

Question 34. During active protein synthesis, some ribosomes seem to occur in groups and are collectively known as :

1. Bound ribosomes
2. Polyribosomes
3. Lysosomes
4. Dictyosomes.

Answer: 2. Polyribosomes

NEET Biology MCQ Cell The Unit of Life Question 35. Ribosomes are present in the cytoplasm as minute particles:

1. Associated with er and are sites for protein synthesis
2. Associated with mitochondria are the sites of glucose oxidation
3. On the cell surface and are concerned with protein synthesis
4. None of the above.

Answer: 1. Associated with er and are sites for protein synthesis

Question 36. Which of the following are prokaryotes?

1. Viruses and rickets
2. Bacteria and archaebacteria
3. Cyanobacteria and mycoplasma
4. Both 2 and 3.

Answer: 4. Both 2 and 3.

Question 37. Ribosomes originate from:

1. Nucleus
2. Er
3. Nucleolus
4. Mitochondria.

Answer: 3. Nucleolus

Question 38. Ribosomes present in a prokaryotic cell are :

1. 70 S type
2. 60 S type
3. 80 s type
4. Both 70s and 80s type.

Answer: 1. 70 S type

Question 39. Sphaerosomes have an affinity for :

1. Sudan black
2. Eosin stains
3. I Leishman’s stain
4. Giemso’s stain.

Answer: 1. Sudan black

NEET Biology MCQ Cell The Unit of Life Question 40. Ribosomes are :

1. Positively charged
2. Negatively charged
3. Amphoteric
4. None of the above.

Answer: 2. Negatively charged

Question 41. Golgi apparatus is present in :

1. Phanerogams
2. Cryptogams
3. All eukaryotes
4. Vertebrates.

Answer: 3. Vertebrates.

Question 42. Dictyosome is also known as :

1. Respiratory particle
2. Ribosome
3. Golgi bodies
4. Peroxisome.

Answer: 3. Peroxisome.

Question 43. Golgi bodies are related to:

1. Excretion
2. Energy liberation
3. Pinocytosis
4. Secretions.

Answer: 3. Pinocytosis

Question 44. Golgi bodies are maximum in :

1. Calyptrogen
2. Root cap
3. Both 1 and 2.
4. Root tip.

Answer: 4. Root tip.

NEET Biology MCQ Cell The Unit of Life Question 45. Which of the following cell organelles are considered to be rich in catabolic enzymes?

1. Endoplasmic reticulum
2. Lysosomes
3. Golgi bodies
4. Mitochondria.

Answer: 2. Lysosomes

Question 46. Which of the following is widely distributed in a cell?

1. Chromoplasts
2. Chloroplast
3. RNA
4. DNA.

Answer: 3. RNA

Question 47. Membranes are found within :

1. Chromosomes, nuclei and mitochondria
2. Cytoplasm, chloroplasts and mitochondria
3. Cytoplasm, nuclei and starch grains
4. Chromosomes, chloroplasts and starch grains.

Answer: 2. Cytoplasm, chloroplasts and mitochondria

Question 48. Most of the hydrolytic enzymes of lysosomes function at :

1. Acidic ph (ph =5)
2. Basic ph
3. Neutral ph
4. Any ph.

Answer: 1. Acidic ph (ph =5)

Question 49. The secretory material is discharged by the Golgi vesicles, from the surface of the cell membrane by:

1. Pinocytosis
2. Endocytosis
3. Reverse pinocytosis
4. Dissolving the cell membrane.

Answer: 3. Reverse pinocytosis

NEET Biology MCQ Cell The Unit of Life Question 50. Mitochondrial DNA differs from nuclear DNA in:

1. Being linear
2. Having a=tandc: g
3. Being highly twisted
4. Lacking binding with the histones.

Answer: 4. Lacking binding with the histones.

Question 51. In the nucleon ema of the nucleus, particles 150- 2004 are seen which resemble:

1. Ribosomes
2. Lysosomes
3. Mitochondria
4. Sphaerosomes.

Answer: 1. Ribosomes

Question 52. Mitochondria can be distinguished from similar-looking particles in living cells by their affinity for a dye called:

1. Acetocarmine
2. Janus green.
3. Eosin
4. Methylene blue.

Answer: 2. Janus green

Question 53. Which of the following observations most strongly support the view that mitochondria contain electron transfer enzymes aggregated into compact association?

1. Mitochondria have a highly folded inner wall
2. Disruption of mitochondria yields membrane fragments which can synthesize ATP
3. Mitochondria in animal embryos tend to concentrate in cells which become a part of the locomotory structure
4. A contractile protein capable of utilising ATP has been obtained from mitochondria.

Answer: 2. Disruption of mitochondria yields membrane fragments which can synthesize atp

Question 54. Within the cell, the site of respiration is:

1. Nucleus
2. Mitochondrion
3. Ribosome
4. Lysosome.

Answer: 4. Lysosome.

NEET Biology MCQ Cell The Unit of Life Question 55. Cristae refer to :

1. Infolding of the inner membrane of mitochondria
2. Infolding of the outer membrane of mitochondria
3. Branches of endoplasmic reticulum
4. Golgi apparatus.

Answer: 1. Infolding of the inner membrane of mitochondria

Question 56. A mitochondrion possesses a :

1. Single membrane
2. Double membrane
3. Three-layered membrane
4. Four-layered membrane.

Answer: 2. Double membrane

Question 57. The existing evidence favours that mitochondria arise;

1. From precursors in the cytoplasm
2. From non-mitochondrial membranes
3. By growth and division of pre-existing mitochondria
4. None of the above.

Answer: 3. None of the above.

Question 58. The Golgi apparatus present in cells synthesizes:

1. Cellulose
2. Hemicellulose
3. Pectin
4. All of the above.

Answer: 4. All of the above.

Question 59. The Golgi apparatus is bounded by :

1. Single unit membrane
2. Cellulose layer
3. Plasma membrane
4. The double unit membrane of lipoproteins.

Answer: 1. Single-unit membrane

NEET Biology MCQ Cell The Unit of LifeQuestion 60. Which one of the following is responsible for the breakdown of parts of the cell and foreign particles in the cell?

1. Ribosome
2. Centrosome
3. Lysosome
4. Golgi apparatus.

Answer: 3. Lysosome

Question 61. The percentage of mitochondrial dna in the cells is:

1. 10% Of total cellular dna
2. L% of total cellular dna
3. 2.5% of total cellular dna
4. None of the above.

Answer: 2. L% of total cellular dna

Question 62. Secondary lysosomes give rise to:

1. Residual bodies
2. Tertiary lysosomes
3. Peroxisome
4. None of the above.

Answer: 1. Residual bodies

Question 63. Lysosomes are considered suicidal bags because they:

1. Kill the neighbouring cells
2. Kin the engulfed bacteria
3. Are responsible for intracellular digestion
4. Oxidise the food in the cells.

Answer: 3. Are responsible for intracellular digestion

Question 64. Lysosome along with the food contents is :

1. Primary lysosome
2. Secondary lysosome
3. Residual bodies
4. Cytosome.

Answer: 2. Secondary lysosome

Question 65. Peroxisomes are bounded by :

1. Single membrane
2. Double membrane
3. Triple membrane
4. No membrane.

Answer: 1. Single membrane

Question 66. Peroxisomes do not have :

1. O-amino acid oxidase
2. B-hydroxy acid oxidase
3. Urate oxidase
4. DNA synthetase.

Answer: 4. Dna synthetase.

Question 67. Bone cells containing lysosomes are:

1. Osteofibrils
2. Osteoclasts
3. Osteoblasts
4. None of the above.

Answer: 2. Osteoclasts

Question 68. Sphaerosomes arise from;

1. Mitochondrion
2. Lysosome
3. E.r.
4. Ribosome.

Answer: 3. E.r.

Question 69. Sphaerosomes are mostly present in :

1. All cells
2. Prokaryotic cells
3. Lipid secreting and storing cells.
4. None of the above.

Answer: 3. Lipid secreting and storing cells.

Question 70. The cellular role of the lysosome is not :

1. Ingestion of foreign bodies
2. Digestion of aged organelles
3. Cell destruction during development
4. Osmoregu location.

Answer: 4. Osmoregu lation.

Question 71. The first scientist to say that plants purify air in the presence of light was:

1. Van Belmont
2. Priestley
3. Ingenhousz
4. Blackman.

Answer: 3. Ingenhousz

Question 72. Thylakoids are presenl in plasrids of :

1. Bacteria
2. Cyanobacteria
3. Higher plants
4. All the above.

Answer: 3. Higher plants

Question 73. The main types of plastids meant for photosynthesis are:

1. Leucoplasts
2. Chromoplasts
3. Chloroplasts
4. None of them.

Answer: 3. Chloroplasts

Question 74. Isolated chloroplasts can synthesize :

1. RNA
2. DNA
3. Proteins
4. None of the above.

Answer: 4. None of the above.

Question 75. Dna genetic material occurs by itself in lower organisms and is combined with proteins as nucleoproteins in higher organisms. The nucleoprotein is organized in higher looms to form:

1. Chromosome
2. Nucleolus
3. Nucleotides
4. Nucleoside.

Answer: 1. Chromosome

Question 76. The nucleus was first discovered by :

1. Walson and crick
2. Bowman
3. Roberr brown hooke.
4. Hooke

Answer: 3. Roberr brown hooked.

Question 77. A nucleus which involves the duplication of chromosomes but fails to divide is known as :

1. Endomitosis
2. Restitution nucleus
3. Euploidy
4. Polyploidy.

Answer: 2. Restitution nucleus

Question 78. Which stain gives purple or violet colour to the chromosome?

1. Feulgen
2. Acetocarmine
3. Acetocein
4. Safranin.

Answer: 1. Feulgen

Question 79. The structure of the nuclear membrane facilitates:

1. Organization of spindle
2. Synapsis of homologous chromosomes during meiosis
3. Nucleo-cytoplasmic exchange of materials
4. Anaphasic separation of daughter chromosomes.

Answer: 3. Nucleo-cytoplasmic exchange of materials

Question 80. The pores of the nuclear membrane have a diameter of :

1. 400Å to 1000Å
2. 600Å to 900Å
3. 100Å to 200Å
4. 700Å to 760Å

Answer: 4. 700Å to 760Å

Question 81. If the nucleus represents its large size in proportion to the cytoplasm of the cell, it indicates that:

1. The cell is dying
2. The nucleus is in the resting phase
3. The nucleus has entered the s-phase of the interphase
4. The cell is about to die.

Answer: 3. The nucleus has entered the s-phase of the interphase

Question 82. An acentric chromosome at metaphase will be :

1. Condensed and lie near the equator
2. Irregularly shaped and lying at one of the poles
3. Condensed and lie at poles
4. Coiled and attached to spindle fibre.

Answer: 1. Condensed and lie near the equator

Question 83. Cytochromes present in the cells are :

1. Electron acceptors
2. Carbon acceptors
3. Hydrogen acceptors
4. Nitrogen acceptors.

Answer: 1. Electron acceptors

Question 84. The parallel layering of membranes in chloroplast is suited for:

1. Maximum light absorption
2. Maximum exposure to enzymes
3. Minimum light absorption so that the cells can maintain their temperature
4. All the above.

Answer: 1. Maximum light absorption

Question 85. Non-photosynthetic plastids are :

1. Amyloplasts
2. Chromoplasts
3. Chloroplasts
4. Both 1 and 2.

Answer: 4. Both 1 and 2.

Question 86. The organelles which occur outer to the cell membrane but inner to the cell wall are :

1. Sphaerosomes
2. Lomasomes
3. Glyoxisomes
4. Peroxisomes.

Answer: 2. Lomasomes

Question 87. Centrioles are :

1. Cylindrical structures
2. Rectangular structures
3. Cuboidal structures
4. Square structures.

Answer: 1. Cylindrical structures

Question 88. The fruits on ripening become coloured, it is due to the:

1. Disintegration of chloroplasts and development of chromoplasts
2. Conversion of chloroplasts to chromoplasts
3. Conversion of chlorophyll into anthocyanin pigment
4. All the above.

Answer: 1. Disintegration of chloroplasts and development of chromoplasts

Question 89. Mitochondria and chloroplasts are believed to be bacterial endosymbionts of cells because:

1. They have their nucleic acids
2. Their inner membrane resembles those of bacteria
3. They do not arise de novo
4. They have all the above attributes.

Answer: 4. They have all the above attributes.

Question 90. Which of the following shows a 9 + 0 arrangement?

1. Centriole
2. Cilia
3. Cilia + centriole
4. Cilia + centriole + flagellum.

Answer: 1. Centriole

Question 91. Cilia and flagella are responsible for :

1. Respiration
2. Locomotion
3. Co-ordination
4. Lipid formation.

Answer: 2. Locomotion

Question 92. Microfilaments are long. Thin fibres 40-60 a :

1. Myosin
2. Actin
3. Tubulin
4. Both 1 and 2.

Answer: 4. Both 1 and 2.

Question 93. The cellular role of the microtubule is not :

1. Protein synthesis
2. Int racell ulai communication
3. Movement
4. Formation of mitotic spindle.

Answer: 1. Protein synthesis

Question 94. One centriole is composed of:

1. Nine triplet peripheral microtubules
2. Nine doublet peripheral microtubules
3. Nine singlet peripheral microtubules
4. None of the above.

Answer: 1. Nine triplet peripheral microtubules

Question 95. Chromosomes having equal arms are known as :

1. Metacentric
2. Acrocentric
3. Telocentric
4. Acentric.

Answer: 1. Metacentric

Question 96. Prokaryotic flagella possess :

1. A helically managed protein molecule
2. Protein membrane-bound libres
3. Unit membrane-enclosed fibre
4. Microtubular “9 + 2” membrane-enclosed structure.

Answer: 1. Helically managed protein molecule

Question 97. The nucleolus is a :

1. Distinct membrane-bound organelle
2. Spheroid ribonucleoprotein only
3. Parr of chromosome
4. All of the above.

Answer: 2. Spheroid ribonucleoprotein only

Question 98. Perinuclear space is the space lying :

1. Outside and around the nuclear membrane
2. Inside and around the nuclear membrane
3. Between the two nuclear membranes
4. None of the above.

Answer: 3. Between the two nuclear membranes

Question 99. An October of four histones complexed with dna is called:

1. Nucleosome
2. Centrosome
3. Chromosome
4. Endosome.

Answer: 1. Nucleosome

Question 100. The core of nucleosome is made up of :

1. H1.h2, a, h,b,h3
2. H1,h2, a,h,b, h4
3. H2 a, h2 b,h3,h1
4. H2 a, h2 b,h3,h4

Answer: 4. H2 a, h2 b,h3,h4

Question 101. Nucleoli are not present in the cells of :

1. Eukaryotes
2. Blue-green algae
3. Maize plant
4. Pancreas.

Answer: 2. Blue-green algae

Question 102. Chromosomes can be specifically stained by :

1. Safranin
2. Acetocarmine
3. Janus green
4. Amine blue.

Answer: 2. Acetocarmine

Question 103. Mature mammalian white blood cells are :

1. Without nuclei
2. With four nuclei
3. Without nucleoplasm
4. With nuclei.

Answer: 4. With nuclei.

Question 104. The undifferentiated fibrillar nucleus is found in :

1. Eukaryotes
2. Cells of higher organisms
3. Prokaryotes
4. Higher animals.

Answer: 3. Prokaryotes

Question 105. Which of the following has a nucleus?

1. Cork cell
2. Sieve tubes
3. Companion cell
4. Vessels.

Answer: 3. Companion cell

Question 106. What will happen if the nucleus is removed?

1. The metabolism will increase
2. The cell will die
3. The metabolism will decrease
4. None of the above.

Answer: 2. The cell will die

Question 107. The process by which dna of the nucleus passes genetic information to mRNA is called :

1. Translocation
2. Transportation
3. Translation
4. Transcription.

Answer: 4. Transcription.

Question 108. The beaded appearance of the chromosome is known as:

1. Centromere
2. Chromomere
3. Centriole
4. Centrosphere.

Answer: 2. Chromomere

Question 109. In mitochondria, cristae act as sites for :

1. Phosphorylation of flavoproteins
2. Protein synthesis
3. Oxidation reduction reactions
4. Breakdown of macromolecules.

Answer: 3. Oxidation-reduction reactions

Question 110. Raphides found in asparagus are crystals of :

1. Calcium carbonate
2. Calcium Citrate
3. Magnesium oxalate
4. Calcium oxalate.

Answer: 4. Calcium oxalate.

Question 111. Chromosome puffs in salivary gland chromosomes are the sites of :

1. Translation
2. Transcription
3. Dna synthesis
4. Dna replication.

Answer: 2. Transcription

Question 112. The fuel-gen nuclear reaction includes the following :

1. Reaction of deoxyribose with leuco fuschin to give purple colour to dna
2. The reaction of ribose with leuco fuschin to give pink colour to rna
3. Removal of purine at the level of the purine deoxyribose glycosidic bond of dna by acid hydrolysis.
4. All the above.

Answer: 3. Removal of purine at the level of the purine deoxyribose glycosidic bond of dna by acid hydrolysis.

Question 113. The chromosome number in plants can be increased by

1. Colchicine treatment
2. Heat treatment
3. Hormonal treatment
4. Breeding with their wild varieties.

Answer: 1. Colchicine treatment

Question 114. Balbiani rings are the characteristics of :

1. Polytene chromosomes
2. Sex chromosomes
3. Ring chromosomes
4. Lampbrush chromosomes.

Answer: 3. Ring chromosomes

Question 115. Chromosomes are made of structural units called

1. Nucleoli
2. Nucleosome
3. Base
4. Centromere.

Answer: 2. Nucleosome

Question 116. One of the following serves as a temporary storage place for proteins and other compounds synthesized by the endoplasmic reticulum :

1. Lysosomes
2. Dictyosomes
3. Sphaerosome
4. Microsome.

Answer: 4. Microsome.

Question 117. Polytene chromosomes are formed when :

1. Chromosome divides but the nucleus does not divide
2. The nucleus divides but the cell does not divide
3. Chromatids divide but the chromosome does not divide
4. The chromosome assumes a lampbrush shape.

Answer: 3. Chromatids divide but the chromosome does not divide

Cell The Unit of Life MCQ for NEET  Question 118. Micrococcal nuclease enzyme :

1. Cuts the dna from a specific site
2. Joins the dna segment
3. Cuts the dna at the junction between nucleosome
4. Binds the dna with histone.

Answer: 3. Cuts the dna at the junction between nucleosome

Question 119. Cenffomere is required for :

1. Replication of dna
2. The poleward movement of chromosome
3. Cytoplasmic cleavage
4. Chromosome segregation.

Answer: 2. Poleward movement of chromosome

Question 120. To determine the ultrastructure of cell organelles, the most likely method of successful observation would be:

1. Phase contrast microscopy
2. Light microscopy
3. Electron microscopy
4. Autoradiography.

Answer: 3. Electron microscopy

Question 121. Mitochondria in a cell are concerned with the formation of:

1. ATP From ADP
2. ATP From Pyruvic Acid
3. Lactic Acid From Citric Acid
4. ADP From ATP.

Answer: 1. ATP From ADP

Question 122. Which of the following representations correctly explains the function of mitochondrion?

Answer: 1.

Cell The Unit of Life MCQ for NEET  Question 123. Who was awarded the Nobel Prize for the synthesis of RNA in 1959 :

1. S. Ochoa
2. A. Korenberg
3. Nirenberg
4. H.G. Khorana.

Answer: 1. S. Ochoa

Question 124. Chlorophyll a is characterized by the side group :

1. Methyl
2. Aldehyde
3. Phytol
4. Ketone.

Answer: 1. Methyl

Question 125. Endoplasmic reticulum was first discovered by :

1. Bell
2. Porter
3. Golgi
4. Altrnan.

Answer: 2. Porter

Question 126. The centrosome is rich in :

1. DNA
2. RNA
3. ATP
4. Enzymes.

Answer: 2. RNA

Question 127. ‘Protein factories’ of the cell to be effective, need :

1. Fe++
2. Cu++
3. Mg++
4. Ca++

Answer: 3. Mg++

Cell The Unit of Life MCQ for NEET  Question 128. In a eukaryotic cell, the region between the nucleus and plasma membrane is called :

1. Junction
2. Nucleoplasm
3. Cytoplasm
4. Lumen.

Answer: 3. Cytoplasm

Question 129. Vacuoles are considered as living organelles because they:

1. Are membrane-bound
2. Have hormones
3. Store enzymes
4. Can arise de novo.

Answer: 1. Are membrane-bound

Question 130. Which of the following is not the correct pairing of structure with function :

1. Golgi complex: breakdown of complex molecules
2. Chloroplast: photosynthesis
3. Mitochondria: production of ATP
4. Sphaerosome: synthesis and storage of fat.

Answer: 1. Golgi complex: breakdown of complex molecules

Question 131. Proteins that are to be utilized outside the cell are synthesized :

1. In the mitochondria
2. On the rear
3. On the ser
4. On free ribosomes.

Answer: 2. On the rear

Question 132. Plant cells are connected by channels through their walls called :

1. Plasmodesmata
2. Desmosomes
3. Tight junction
4. Desmotubules.

Answer: 1. Plasmodesmata

Question 133. Haploid plants can be obtained by culturing :

1. Root tips
2. Young leaves
3. Endosperm
4. Pollen grains.

Answer: 4. Pollen grains.

Question 134. Pyrenoids are centres for:

1. Fat production
2. Starch formation
3. Protein formation
4. Enzyme foundation.

Answer: 2. Starch formation

Cell The Unit of Life NEET Questions Question 135. Bacteria are examples of :

1. Prokaryotic cell
2. Eukaryotic cell
3. Organelles
4. Plastids.

Answer: 1. Prokaryotic cell

Question 136. Which of the following is not found in prokaryotic cells?

1. Plasma membrane
2. Cell wall
3. Nuclear envelope
4. Ribosomes.

Answer: 3. Nuclear envelope

Question 137. How many membranes comprise the nuclear envelope?

1. None
2. One
3. Two
4. Three.

Answer: 3. Two

Question 138. Which of the following moves regularly frorn the nucleus to the cytoplasm?

1. Glycogen
2. Rna
3. Dna
4. Cholesterol.

Answer: 2. Rna

Question 139. The plastids that give fruits and flowers their orange and yellow colour are the :

1. Leucoplasts
2. Chloroplasts
3. Chromoplasts
4. Protoplasts.

Answer: 3. Chromoplasts

Question 140. The types of cellular organelles that transform energy are :

1. Chromoplasts and leucoplasts
2. Mitochondria and chloroplasts
3. Mitochondria and chromoplasts
4. Chloroplasts and leucoplasts.

Answer: 3. Mitochondria and chromoplasts

Question 141. Lysosomes contain enzymes capable of:

1. Aerobic cellular respiration
2. Digesting part of the cell
3. Synthesizing proteins
4. Synthesizing lipids.

Answer: 2. Digesting part of cell

Cell The Unit of Life NEET Questions Question 142. Mitochondria are found :

1. In all cells
2. Only in plant cells
3. Only in animal cells
4. All eukaryotic cells.

Answer: 4. All eukaryotic cells.

Question 143. Which of the following observations most strongly supports the view that mitochondria contain electron transfer enzymes aggregated into compact association :

1. Mitochondria have a highly folded inner wall
2. Disruption of mitochondria yields membrane fragments which can synthesise ATP.
3. Mitochondria in animal embryos tend to concentrate in cells which become part of locomotory structures.
4. A contractile protein is capable of utilisation atp has been obtained from mitochondria.

Answer: 2. Disruption of mitochondria yields membrane fragments which can synthesise ATP

Question 144. Hydrogenosomes (identified in 1997) have double membrane help in energy generation in :

1. Dinoflagellates
2. Trichomionids
3. Diatoms
4. All eukaryotes.

Answer: 2. Trichomionids

Question 145. Human sperm cells move by :

1. Cilium
2. Flagellum
3. Basal body
4. Hair.

Answer: 2. Flagellum

Question 146. Plant cells are connected by channels through their walls called:

1. Plasmodesmata
2. Desmosomes
3. Tight junctions
4. Gap junctions.

Answer: 1. Plasmodesmata

Cell The Unit of Life NEET Questions Question 147. Glycolysis is a process found in :

1. Eukaryotic cell
2. Anaerobic bacteria
3. Most muscle cells
4. Virtually all cells.

Answer: 4. Virtually all cells.

Question 148. The protoplasm is:

1. True solution
2. Emulsion
3. Suspension
4. Reversible colloidal solution.

Answer: 4. Reversible colloidal solution.

Question 149. The cell organelle common in protista and monera is :

1. Lysosome
2. Chloroplasts
3. Ribosome
4. Vacuole.

Answer: 3. Ribosome

Question 150. A striking difference between a plant cell and an animal cell is the presence of the former:

1. Chloroplast
2. Cell wall
3. Centrosome
4. Plasmalemma.

Answer: 2. Cell wall

Question 151. In which component of a mitochondrion atp is synthesized

1. Crista
2. Matrix
3. Fo-fr complex
4. Plasmalemma.

Answer: 3. Fo-fr complex

Cell The Unit of Life Biology NEET Question 152. Photorespiration occurs in plant cells in :

1. Dictyosome
2. Glyoxisome
3. Peroxisomes
4. Endoplasmic reticulum.

Answer: 3. Endoplasmic reticulum.

Question 153. Golgi apparatus is lacking in :

1. Liver cells
2. Higher plants
3. Blue-green algae
4. Yeasts.

Answer: 3. Blue-green algae

Question 154. Polysome is a chain of :

1. Pinosome
2. Ribosomes
3. Phagosomes
4. Lysosomes.

Answer: 2. Ribosomes

Question 155. Lysosomes containing inactive enzymes are called :

1. Autophagosomes
2. Residual bodies
3. Secondary lysosomes
4. Primary lysosomes.

Answer: 4. Primary lysosomes.

Cell The Unit of Life Biology NEET Question 156. The chloroplast thylakoids are in the form of;

1. Interconnected sacs
2. Independent discs
3. Interconnected tubules
4. Stacked discs.

Answer: 1. Interconnected sacs

Question 157. The pattern of microtubule organization in a centriole is:

1. 9+0
2. 9+1
3. 9+2
4. 9+3.

Answer: 1.9+0

Question 158. In man the amount of water is about :

1. 35%
2. 55%
3. 1O%
4. 90%.

Answer: 1. 35%

Question 159. The basal body could be another name for centriole given internal structures when :

1. It gives rise to spindle fibres
2. Lt divides during mitosis
3. It gives rise to cilia or flagella
4. Lt gives basic reactions.

Answer: 3. It gives rise to cilia or flagella

Question 160. How much energy is released for each molecule of oxygen used in :

1. 114.5 kcal
2. 124.5 kcal
3. 134.5 kcal
4. 144.5 kcal.

Answer: 3. 134.5 kcal

Question 161. What would be a good example of the occurrence of three types of plastids in a developing organ?

1. Radish
2. Turnip
3. Brinial
4. Tomato.

Answer: 4. Tomato.

Cell The Unit of Life Biology NEET Question 162. Which of the following is the chief energy food in a cell?

1. Carbohydrates
2. Nucleotides
3. Lipids
4. Proteins.

Answer: 1. Carbohydrates

Question 163. Water enters the cell by :

1. Endosmosis
2. Pinocytosis
3. Phagocytosis
4. All of the above.

Answer: 4. All of the above.

Question 164. Golgi apparatus resembles :

1. Ser
2. Rer
3. Nuclear envelope
4. None of the above.

Answer: 1. Ser

Question 165. Materials enter the Golgi complex at :

1. Cis region
2. Trans region
3. Medial region
4. Trans golgi reticulum.

Answer: 1. Cis region

Question 166. The enzyme peptidyl transferase is present in :

1. Smaller subunit of the ribosome
2. Larger subunit of ribosome
3. Groove between smaller and larger subunits
4. In the cytoplasm.

Answer: 2. Larger subunit of ribosome

Question 167. Autophagic vacuoles (vesicles) digest :

1. Pinosome content
2. Phagosome content
3. Cell organelles
4. Microorganisms.

Answer: 3. Cell organelles

Question 168. Lysosomes help in :

1. Fertilization
2. Insulin processing
3. Contraception
4. All of the above.

Answer: 4. All of the above.

Question 169. F is composed of :

1. Five polypeptides
2. 3 Polypeptides
3. 3 Polypeptides and accessory polypeptides
4. A, b, c, d and e polypeptides.

Answer: 4. A, b, c, d and e polypeptides.

Question 170. A quant some contains :

1. 250 Chlorophyll molecules
2. 350 Chlorophyll molecules
3. 450 Chlorophyll molecules
4. 245 Chlorophyll molecules.

Answer: 1. 250 Chlorophyll molecules

Question 171. The flagellum of a eukaryotic cell shows :

1. 9 + 0 Arrangement
2. 9 + 2 Arrangement
3. 1 + 2 Arrangement
4. 2 + 9 Arrangement.

Answer: 2. 9 + 2 Arrangement

Question 172. Select the self-duplicating organelle :

1. Mitochondria
2. Plastids
3. Centriole
4. All of these.

Answer: 4. All of these.

Question 173. Peroxisomes and glycosomes are :

1. Energy transducers
2. Membrane-less organelles
3. Microsomes
4. Microbodies.

Answer: 4. Microbodies.

Question 174. Lysosomes with cell organelles are called :

1. Primary lysosomes
2. Secondary lysosomes
3. Autophagosomes
4. Residual bodies.

Answer: 3. Autophagosomes

Question 175. Golgi bodies are involved in :

1. Excretion
2. Secretion
3. Atp synthesis
4. Rna synthesis.

Answer: 2. Secretion

Question 176. The chloroplasts develop limo :

1. Er
2. Dictyosome
3. Nuclear membrane
4. Proplastids.

Answer: 4. Proplastids.

Question 177. The supporting framework of a cell consists of :

1. Microfilaments
2. Microtubules
3. Both of these
4. None of the above.

Answer: 3. Both of these

Question 178. A chromosome having equal arms is called :

1. Metacentric
2. Submetacentric
3. Acrocentric
4. Telocentric.

Answer: 1. Metacentric

Question 179. Chromosomes are stained with :

1. Eosin
2. Safranin
3. Acetocarmine
4. Borax carmine.

Answer: 3. Acetocarmine

Question 180. Golgi apparatus is most abundantly found in :

1. Muscle cells
2. Neurons
3. Red blood cells
4. Pancreatic cells.

Answer: 4. Pancreatic cells.

Question 181. Mechanical support to the cell is provided by :

1. Golgi bodies
2. Microfibrils
3. E.r.
4. Chromatin.

Answer: 3. E.r.

Cell The Unit of Life Biology NEET Question 182. The function of the centrosome is :

1. Initiation of cell division
2. Inhibition of cell division
3. Termination of cell division
4. None of the above.

Answer: 4. None of the above.

Question 183. A chromosome having a subterminal centromere is :

1. Telocentric
2. Acrocentric
3. Submetacentric
4. Metacentric.

Answer: 2. Acrocentric

Question 184. Which structure is present in animal cells but is absent in plant cell?

1. Centrioles
2. Golgi apparatus
3. Mitochondria
4. Endoplasmic reticulum.

Answer: 1. Centrioles

Question 185. The smallest cell organelle is :

1. Mitochondria
2. Microfilament
3. Microtubule
4. Ribosome.

Answer: 4. Ribosome.

Question 186. Which of the following is the vacuolar membrane?

1. Cell membrane
2. Tonoplast
3. Karyotheca
4. Er.

Answer: 4. Er.

Question 187. Select the amphipathic organic compound :

1. Fibroin.
2. Proteins
3. Phospholipids
4. Nucleotides.

Answer: 3. Phospholipids

Question 188. The plastids present in red algae are :

1. Chloroplast
2. Rhodoplasts
3. Phaeoplasis
4. Leucoplasts.

Answer: 2. Rhodoplasts

Question 189. Dark reactions of photosynthesis occur in :

1. Stroma
2. Inter membrane space
3. Thylakoids
4. Axe of above.

Answer: 1. Stroma

Question 190. Microtubules were first seen in :

1. Medullated nerve fibre
2. Muscle fibre
3. Non-medullated nerve fitrre
4. Cellulose fibre.

Answer: 1. Medullated nerve fibre

Cell The Unit of Life Biology NEET Question 191. Maps are found in :

1. Microtubules
2. Intermediate filament
3. Microfilg+ents
4. Microtrabeculae.

Answer: 1. Microtubules

Question 192. Turgor pressure in plant cells is generally, between:

1. 5 And 20 atm
2. 20 And 40 atm
3. 10 And 30 atm
4. 1 And 5 atm.

Answer: 1. 5 And 20 atm

Question 193. Hydrogenosomes are found in certain :

1. Amoebae
2. Flagellates
3. Ciliates
4. Sporozoans.

Answer: 2. Flagellates

Question 194. The nucleus has ribosomes attached to :

1. Inner membrane
2. Outer membrane
3. Chromatin fibres
4. All of the above.

Answer: 2. Outer membrane

Question 195. Which of the following is a major component of the nucleus?

1. Dna
2. Lipids
3. Rna
4. Proteins.

Answer: 4. Proteins.

Question 196. The nucleolus is especially rich in :

1. Dna and proteins
2. Rna and proteins
3. Dna and proteins
4. Rna and lipids.

Answer: 3. Dna and proteins

Question 197. Chromosomes are best seen in :

1. Interphase
2. Metaphase
3. Anaphase
4. Telophase.

Answer: 3. Anaphase

Question 198. In spermatogenesis, the acrosome of the sperm is formed by:

1. Mitochondria
2. Nucleus
3. Lysosome
4. Golgi complex.

Answer: 3. Lysosome

Question 199. Polytene chromosomes were first seen in :

1. Drosophila
2. Fruit fly
3. Chironomus larva
4. None of the above.

Answer: 3. Chironomus larva

Question 200. Synaptonemal complex is associated with :

1. Polytene chromosome
2. Lampbrush chromosome
3. Mitotic chromosome
4. Paired meiotic chromosomes.

Answer: 4. Paired meiotic chromosomes.

Question 201. The beaded areas on chromosomes are known as :

1. Centromere
2. Cristae
3. Chromomeres
4. Cistron.

Answer: 3. Chromomeres

Question 202. Stem cells is an alternative term for :

1. Dedifferenriared cells
2. Redifferentiated cells
3. Undifferentiated cells
4. Differentiated cells.

Answer: 3. Undifferentiated cells

Question 203. Cell biology is the study of :

1. Cell structure
2. Cell Function
3. Cell division
4. Cell structure and function.

Answer: 4. Cell structure and function.

Question 204. Which of the following is time?

1. A cotton fibre is made up of 1500 fibrils
2. A fibril has 250 microfibrils
3. A microfibril has 20 micelles
4. All of above.

Answer: 4. All of the above.

Question 205. Channel has been discovered by :

1. Singer and Nicholson
2. Garnier
3. Robinson and brown
4. Nehar and salesman

Answer: 1. Singer and Nicholson

Question 206. Pelviz et al discovered :

1. Microtubules
2. Microfilaments
3. Centriole
4. Peroxisome.

Answer: 1. Microtubules

NEET Biology MCQ Cell The Unit of Life Question 207. Nucleoplasmin occurs inside :

1. Chromatin
2. Nucleolus
3. Nucleoplasm
4. Nucleopores.

Answer: 4. Nucleopores.

Question 208. Match the items of column 1 with the items of column 2

1. (1-D), (2-E), (3-F), (4-A) (5-B), (6-C)
2. (1-D), (2-E), (3-A), (4-F), (5-B), (6-C)
3. (1-D), (2-E) (3-F), (4-C) (5-A), (6-B)
4. (1-D), (2-F), (3-C), (4-E), (5-A), (6-B).

Answer: 3. (1-D), (2-E) (3-F), (4-C) (5-A), (6-B)

Question 209. Match the items of column 1 with column 2

1. (1- c), (2- d), (3- e), (4- b), (5- a)
2. (1- c), (2- d), (3- b), (4- c), (5- a)
3. (1- c), (2-d), (3- a), (4-b), (5- e)
4. (1 – c), (2- d), (3- e), (4- a). (5- b).

Answer: 1. (1- c), (2- d), (3- e), (4- b), (5- a)

Question 210. Match the items of column 1 with the items of column 2

1. (1 – C), (2 – d), (3 – a), (4 – b), (5 – e)
2. (1- C), (2 – a), (3 – d), (.4 – e), (s – b)
3. (1- C), (2 – d), (3 – e), (4 – a), (5 – b)
4. (1- C), (2 – d), (3 – b), (4 – a), (5 – e).

Answer: 3. (1- C), (2 – d), (3 – e), (4 – a), (5 – b)

Question 211. Match the terms in column a with suitable terms

1. (1-c), (2-f), (3-a), (4-e) (5-b),(6-d)
2. (1-c), (2-f), (3-a), (4-b), (5-d),(6-e)
3. (1-c), (2-f) (3-a), (4-e) (5-d),(6-b)
4. (1-c), (2-d), (3-a), (4-e), (5-b),(6-f)

Answer: 1. (1-c), (2-d), (3-a), (4-b) (5-e)

Question 212. Enzymes associated with converting fats to carbohydrates are located in which organelle?

1. Liposomes
2. Golgi bodies
3. Glyoxysomes
4. Microsomes.

Answer: 3. Glyoxysomes

Question 213. Which of the following is covered by a single membrane?

1. Nucleus
2. Mitochondria
3. Chloroplast
4. Sphaerosomes.

Answer: 4. Sphaerosomes.

Question 214. Dna is ‘mainly’ found in :

1. Nucleus only
2. Cytoplasm
3. Nucleus and cytoplasm
4. All the above.

Answer: 1. Nucleus only

Question 215. What is common between chloroplasts, chromoplasts and leucoplasts?

1. Presence of pigements
2. Possession of thylakoids and Gama
3. Storage of starch, proteins and lipids
4. Ability to multiply by a fission-like process.

Answer: 4. Ability to multiply by a fission-like process.

Question 216. Organelle connected with glycoside

1. Ribosome
2. E.r.
3. Mitochondrion
4. Chloroplast.

Answer: 2. E.r.

Question 217. The Centre of phosphorylation is :

1. Ribosome
2. Oxisome
3. Peroxisome
4. Sphaerosome.

Answer: 3. Peroxisome

NEET Biology Gymnosperms

1. Gymnosperms are the ancestral seed-producing plants. The term ‘Gymno’ signifies nude, whereas ‘Sperma’ denotes a seed. The term gymnosperms refers to plants that possess naked seeds.
2. Approximately 900 species of extant gymnosperms exist, with conifers comprising around 500 species of this category.

Features of Gymnosperms

1. J. Gymnosperms are mainly woody plants represented by trees, shrubs etc. They are perennials.
2. They bear tap roots. They may exhibit association with algae to form coralloid roots (Cyras) or with fungus to form mycorrhizal roots (Pinus).
3. Leaves may be of one or two kinds i.e. foliage leaves and scale leaves. Leaves may be reduced (Ephedra), needle-like (Pinus) or large and pinnately compound (Cycas).
4. The ovules arc orthotropus and covered by a single integument which is usually made up of outer fleshy, middle stony and inner fleshy layers.
5. The main plant body is sporophyte which is heterosporous. The gametophytes are reduced. The female gametophyte is never shed. (t. The female gametophyte is constituted by haploid endosperm on which 2-8 archegonia are present. Neck canal cells are absent.
6. Sexual reproduction is of the oogamous type.
7. Male cones bear microsporophylls on which microsporangia are borne.
8. Microspores (pollen grains) are formed in the microsporangia and they lead to the development of male gametophytes.
9. The pollen tube grows through the female gametophyte and reaches near the archegonium.
10. Syngamy occurs and oospore (2n) is fonned.
11. All gymnosperms arc wind-pollinated. They are anemophilous.
12. After fertilization, the oospore forms the embryo. Since they are formed by many oospores, each oospore forms the embryo. So there is the phenomenon of polyembryony.
13. Ovules arc transformed into seed.
14. Seeds contain two to many cotyledons which on germination give rise to diploid plants hence they arc polycotylcdonous.

Read and Learn More NEET Biology Notes

Gymnosperms NEET Notes

Classification of Gymnosperms

NEET Biology Gymnosperms Life Cycle Of Pinus

It is an exposed seed-bearing phanerogam. It is found in hills at different altitudes. The main plant body is a sporophyte. It is a large large-sized tree, with roots, stems and leaves.

Stem has long and dwarf shoots, the former shows unlimited growth and the latter shows limited growth. Leaves are scale and foliage (needle-like and green).

Dwarfbranches fall at regular intervals so the tree is evergreen. The plant attains a conical shape due to the excurrent mode of branching.

The stem shows a normal type of secondary growth. The wood is pyroxylin (hard and compact woods and monocyclic has only one ring of xylem. The bordered pits are uniseriate.

The plants are monoecious. The male and female reproductive organs are in the form of well-organized cones. The short male cones or strobila are seen clustered on the tip of the young shoot.

Several microsporophylls arc spirally arranged on an axis or thalamus. The male cone therefore is is aflower and not an inflorescence. On the lower surface of each microsporophyll are two or more microsporangia containing numerous microspore mother cells which divide meiotically to produce microspores or pollen.

At maturity, each microsporangium splits open by a longitudinal slit. Then pollen grains are released and dispersed by wind.

The female cone is a complex structure. The axis beats some spirally arranged bract scales in the axil each of which produces an ovuliferous scale. Each ovuliferous scale bears on its surface two ovules or megaspomngin.

The ovule consists of u muss covered by an integument growing from its base. It is differentiated into three lasers. The integument is often at the top forming a micropylc or oblique pore.

The two oxuliferxnis scales with the ovules are considered to form a separate shoot. The strobilus (connect is a compound one homologous with an inflorescence.

The cone takes about 2b months to reach maturity. Within the nucellus is present a single megaspore mother cell which divides by meiosis to form a linear tetrad of megaspores. The lowermost of the 4 megaspores remains functional. Gamclophvtcs.

Gymnosperms NEET Study Material

The pollen grains and die megaspores are the first cells of the male and female gametophyte respectively. At the time of pollination, pollen grains are shed at the 4-celled stage (2 prothallial cells, a generating cell and tube cell).

During pollination the whole atmosphere becomes yellow. People call it as Showers of Sulphur. The female gametophyte bears 1-5 (usually 3) archegonia. The archegonium consists of a venter and a short neck of 4 cells in two tiers.

The neck canal cell is absent. In the venter, there is a venter canal cell and a large oosphere characterised by a prominent nucleus and dense cytoplasm.

Fertilization is siphonogamous with the help of a pollen tube. The zygote or oospore produces an embryo.

Development is meroblastic. Sometimes more than one embryos are formed from the same zygote. This is called Cleavage polyembryony. Seeds are winged. Germination is epigeal. The seeds are polycotyledonous.

The three generations in the seed are:

1. Testa, tegmen and perisperm represent parental sporophyte
2. Endosperm represents female gametophyte
3. Plumule, radicle, cotyledon represent future sporophyte.

NEET Biology Gymnosperms Some Facts Regarding The Life Cycle Of Cycas

• Cycas. Commonly called ‘sagopalm’ or ‘Cocopalm’ is a Gymnosperm of the order Cycadales and family Cycadaceae.
• Out of a total of 20 spaces. 6 species of Cycas are found in India (C. circinalis, C pcctinala. C. rumpliii, C. beddomei, C. revoluta and C. siamensis).
• Cycas appears like a palm and differentiates itself into roots, stems and leaves.
• Roots are of two types, i.e. normal tools which grow deep into the soil and coralloid roots which are coral-like, dichotomously branched, negatively geotropic and green in colour because of the presence of some blue-green algae(For example Nostoc, Anabaena, etc.).
• Stem is erect, stout and unbranched (rarely branched), and the leaves are of two types foliage leaves and scaly leaves.
• Foliage leaves are large, pinnately compound and reach up to 3 to 5 feet or more in length. Young leaflets are circinately coiled. 80-100 pairs of leaflets may be present in each leaf.
• Cycas is strictly dioecious = unisexual = Imperfect.
• Normal roots are generally radial diarchs.
• Coralloid roots are generally radial and exarch Triarch and always contain an algal zone in the cortex. The algal zone contains species of Anabaena, Nostoc, a few diatoms and some bacteria such as Azotobacter and Pseudomonas.
• Old stems contain 2-22 xylem rings showing polycystic condition. Mucilage canals are also present.
• In the rachis, the vascular bundles are arranged in an omega (Q)-shaped manner. The xylem is diploxylic i.e. consists of a centripetal xylem and a centrifugal xylem.
• Leaflets contain transfusion tissue, sunken stomata, and diplomatic xylem mesophyll differentiated into palisade and spongy parenchyma. Margins of the wings of the leaflet are straight in C. circinalis while revoluted in C. revoluta.
• Male cones and female megasporophylls or ovuliferous scales are present on different plants. The male cone reaches upto about 50 cm in height and contains several microsporophylls.
• On the abaxial (lower) surface of each microsporophyll are present thousands of microsporangia in groups of 3 to 5. Each group of microsporangia is called a sorus. Several pollen grains or microspores are found in each microsporangium.
• True female cones are absent. Female reproductive organs are present in the form of leaf-like megasporophylls.
• Each megasporophyll contains an upper dissected or pinnate leafy portion and a stalk. Ovules remain arranged in two rows on the stalk of the megasporophyll.
• Megasporophylls remain covered with many brown-coloured hairs.
• Cycas circinalis contains the largest ovule amongst the living gymnosperms of the world. It measures about 6 cm in length.
• Mature ovule is orthotropous and unitegmic. The single integument consists of 3 layers, i.e. outer fleshy layer, middle stony layer and inner fleshy layer.
• A hollow pollen chamber is present in the nucellar beak. In the female gametophyte are present two archegonia near the archegonial chamber.
• Pollination is directed by wind.
• The time between pollination and fertilization is 12-15 months.
• Dependence on water is overcome by siphonogamy.
• After fertilization, the ovule as a whole develops into a seed.
• Cycas show an alternation of generations.

Gymnosperms NEET Question Bank

NEET Biology Gymnosperms Economic Importance Of Gymno Sperms

Gymnosperms are of great use in human welfare.

1. Timber. Conifers provide a valuable limber Example Pinus roxburghii, Pinus longifolia (chir) Cedrus deodara {deodar), Pinus excelsa (kail)
2. Protection from soil erosion. Gymnosperms commonly grow on slopes of hills where they hold the soil particles firmly against running water during the rains.
3. Food. Seeds of Pinus ginardiana (chilgoza) are eaten after roasting. Roasted endosperm ofGinkgo, seed kernels of some Cycas species and Gnetum are edible. Sago grains can be obtained from the stem of Cycas. The latter is. therefore also called Sago Palm. Tender leaves of Cycas are cooked or added to curries.
4. Abies balsamia yields a gum used as Canada balsam in microscopic studies.
5. The resin obtained from the trunks of Finns roxburghii, P. wallichiana and P. insularis is used in the manufacture of turpentine oil and resin.
6. Medicines. Drug ephedrine (obtained from stems of Eplicdra species) is given for asthma and bronchitis. Decoction of the stem is used to treat rheumatism. A gum from Cycast and C. circinalis is known to treat tumours. Taxol is an anticancer drug obtained from Tuuis.
7. Sago. Cycas circinalis yields a starch Sago which is used as food.
8. Sabudana is obtained from Cycas revoluta.
9. Berries of juniper are used for flavouring alcoholic beverages like gin etc.
10. Ornamental. Ginkgo (maidenhair tree), Tlnija, Pinus, Cycas, and Araucaria (monkey’s pu/./.lc) are grown for their ornamental value.
11. Cedarwood oil is obtained from the heartwood of Juniperus Virginia.
12. Young plants ofP. merkusii (merkus pine) are used as raw material in the manufacture of craft paper.
13. Wood of several gymnosperms is used in the preparation of pulp, e.g., Pinus, Abies, Picea, lurex, Tsuga, etc.
14. Iannins. Bark of Tsuga canadensis (Hemlock) is used in tanning.
15. linoleum. Saw dust formed during the preparation of timber is used in the formation of linoleum.
16. Coverages and narcotics. Leaves of Tsuga canadensis are used in the preparation of tea. Wine is fermented from seeds and stems of Cvcas revoluta.

1. Unitcgmic ovules are where the integument is differentiated into outer sarrotesta, middle sclerotesta and inner sarcotcsta.
2. Chilgoza is the fruit of the gymnosperm and cannot be called true because the true fruit scientifically is a ripened ovary which is absent in the gymnosperm.
3. Gymnosperms are naked-seeded plants.
4. In Pinus. pollen grains are winged.
5. Dwarf shoots arise in the axil of bracts on long shoots.
6. The remnant nucellar tissue present within the seed covering of the embryo is called perisperin.
7. Transversely oriented conducting parenchyma tissue of pine leaf is called transfusion tissue.
8. Medicinally most important gymnosperms are Taxus and Ephedra.
9. The only gymnosperm which lacks haploid endosperm is Gnetum.
10. Pinus also exhibits cleavage polyembryony.
11. The largest gametes of the biological kingdom belong to Cycas circinalis.
12. Screw pine is the common name for Pandanus. Gnetum is an advanced gymnosperm. Ginkgo and Cycas arc the living fossils. Pimts is a conifer.
13. The mature ovule of Cycas circinalis may reach upto 6 cm long and 4 cm in diameter and the Sperms arc is visible with the naked eye.
14. Xylcm lacks vessels in gymnosperms (non-porous). Vessels have been reported in Gnetum, Ephedra and Welwitschia.
15. In gymnosperm, endosperm is haploid and develops before fertilization.
16. About two hundred million years ago, the gymnosperms formed the dominant vegetation on the earth.
17. Ginkgo biloba is called a living fossil.

Gymnosperms NEET Previous Year Questions

NEET Biology Gymnosperms Quanta To Memory

• Gnetum exhibits similarities with Angiosperms and is a sophisticated representative of the gymnosperms.
• The red wood of China is Pinus longifera.
• Conifers do not discard their foliage.
• Gymnosperm wood Manoxylic timber. Cambial activity is ephemeral; the cortex and pith are expansive; parenchymatous rays are wide; the wood is fragile and commercially unviable. Illustration: Cycas.
• Pycnoxylic timber. Cambial activity is prolonged; cortex and pith are diminished; parenchymatous rays are scarce; wood is dense and robust; wood is commercially significant and utilized as high-quality lumber. Illustration: Pinus.
• Gymnosperms are perennial plants.
• Gnetales possess vessels in the xylem, such as Ephedra and Gnetum.
• The resin duct is a schizogenous hollow generated by the separation of cells.
• In Gymnosperms, wood vessels are missing, consisting solely of tracheids.
• In gymnosperms, ovules are exposed and lack an ovary.
• Hydrostereone (Transfusion Tissue) Internal tissue in gymnosperm leaves comprises parenchymatous and tracheidial cells that function as lateral veins.
• In Cycas, the plants are dioecious, with male and female cones produced on separate individuals.
• In Bryophytes, Pteridophytes, and Gymnosperms, the female reproductive organs are termed archegonia, so referred to as archegoniate.
• In gymnosperms, the archegonium venter is not encased by sterile vegetative cells of the jacket.
• In gymnosperms, the nucellus secretes a pollen drop that facilitates the collection of pollen grains within the ovule’s pollen chamber.
• Pollen grains are haploid, and the endosperm of gymnosperms is also haploid; hence, their chromosomal numbers are identical.
• Ginkgo is a living fossil due to its flagellated male gametes. The Nucellus apex excretes sugar droplets to entice pollen, hence referred to as pollen drop.
• Essential oils obtained from gymnosperms include Cedar leaf oil from Thuja occidentalis. ‘Oil of Cade’: Juniperus oxycedrus Oil of Hemlock-spruce: Tsuga canadensis
• Cedarwood oil: Juniperus virginiana. Gymnosperms originated during the Upper Carboniferous epoch of the Paleozoic era, approximately 280 million years ago. Xylem exhibits diplomacy when it is centrifugal, as observed in the rachis of Cycas sp.

NEET Biology Gymnosperms Questions From Competitive Examinations

Question 1. Larges ovules, trees and gametes are found in:

1. Monocots
2. Dicots
3. Both a and b
4. Gymnosperms.

Answer: 4. Gymnosperms.

Question 2. The wood of Finns is:

1. Manoxylic and homozygous
2. Manoxylic and heterozygous
3. Pycnoxylic and homozygous
4. Pycnoxylic and heterozygous.

Answer: 3. Pycnoxylic and homozygous

Question 3. Male cone of pinus possesses

1. Magasporophylls
2. Microsporophylls
3. Anthers
4. Ligules.

Answer: 2. Microsporophylls

Question 4. Which one of the following has not changed for the last several thousand years?

1. Dryopteris
2. Gnetum
3. Ginkgo
4. Palms.

Answer: 3. Ginkgo

Question 5. The algal zone is characteristic of:

1. Coralloid root of cycas
2. The normal root of cycas
3. The normal root of pinus
4. Mycorrhizal root of pinus.

Answer: 1. Naked ovules

Gymnosperms NEET Mcqs

Question 6. Cycas have two cotyledons but not included in angiosperms because of:

1. Naked ovules
2. Seems like monocot
3. Circinate praxis
4. Compound leaves.

Answer: 1. Naked ovules

Question 7. Number of ovules present over megasporophyll of cycas is :

1. 1—2
2. 2—12
3. 12—24
4. 24—48.

Answer: 2. 2—12

Question 8. The endosperm of gymnosperms is:

1. Haploid
2. Diploid
3. Triploid
4. Tetraploid.

Answer: 1. Haploid

Question 9. A microsporophyll of pinus has :

1. Two adaxial microsporangia
2. Two abaxial microsporangia
3. One abaxial microsporangium
4. Four abaxial microsporangia.

Answer: 1. Two adaxial microsporangia

Question 10. Top-shaped multiciliale male gametes, and the mature seed which bears only one embryo with two cotyledons, are characteristic features of :

1. Polypetalous angiosperms
2. Gamopetalous angiosperms
3. Conifers
4. Cycads.

Answer: 2. Gamopetalous angiosperms

Question 11. The tallest tree is:

1. Sequoia
2. Eucalyptus
3. Pinus
4. Ranunculus.

Answer: 1. Sequoia

Question 12. Cycas is a gymnosperm because of :

1. Naked sweet without fruit.
2. Living fossils
3. Vessels present in xylem
4. None of the above.

Answer: 1. Naked seet without fruit.

Question 13. Select one of the following pairs of important features distinguishing gnetum from cycas and pinus and showing affinities with angiosperms:

1. Perianth and two integuments
2. Embryo development and apical meristem
3. Absence of resin duct and leaf venation
4. Presence of vessel elements and absence of archegonia.

Answer: 4. Presence of vessel elements and absence of archegonia.

Question 14. In which one of the following male and female gametophytes do not have free living independent existence?

1. Polytrichum
2. Cedrus
3. Ptcris
4. Funaria.

Answer: 2. Cedrus

Gymnosperms NEET Mcqs

Question 15. The gametophyte is not an independent, free-living generation in:

1. Polytrichum
2. Adiantum
3. Marchantia
4. Pinus.

Answer: 4. Pinus.

Question 16. Cycas and adiantum resemble each other in having :

1. Motile sperms
2. Cambium
3. Vessels
4. Seeds.

Answer: 1. Motile sperms

NEET Biology Phylum Porifera Multiple Choice Questions

Question 1. Approximately what percentage of existing animal species are invertebrates?

1. 20%
2. 50%
3. 70%
4. 95%

Answer: 4. 50%

Question 2. Which of the following is not a characteristic of organisation in the kingdom Animalia?

1. Storage of carbohydrates as starch
2. Multicellularity
3. Obtaining nutrients by ingestion
4. Having eukaryotic cells without wails.

Answer: 1. Multicellularity

Question 3. Most sponges are :

1. Bilaterally symmetrical
2. Radially symmetrical
3. Vertically symmetrical
4. Asymmetrical.

Answer: 4. Asymmetrical.

Question 4. Water exits from a sponge through the :

1. Osculum
2. Spicule
3. Choanocyte
4. Amoebocyte.

Answer: 1. Osculum

Read and Learn More NEET Biology Multiple Choice Question and Answers

MCQs on PoriferaQuestion 5. Which of the following is not a function of amoebocytes in a sponge?

1. Secretion of skeletal materials
2. Control of pores by contraction
3. Transport of food to the epidermal cells
4. Participation in reproduction.

Answer: 2. Control of pores by contraction

Question 6. Which of the following is not true of reproduction in sponges?

1. Asexual reproduction by gemmules
2. Asexual reproduction by budding
3. Internal sterilization
4. Gamete production by epidermal cells.

Answer: 4. Gamete production by epidermal cells.

Question 7. Amoebocyte control of water entry

Which of the following sets is correct

1. (A-1), (B-2), (C-3), (D-4) (E-5)
2. (A-1) (B-3) (C-2) (D-4) (E-5)
3. (A-v) (B-2) (C-1) (D-3) (E-5)
4. (A-4) (B-2) (C-1) (D-3) (E-5).

Answer: 3. (A-v) (B-2) (C-1) (D-3) (E-4)

Question 8. The mode of digestion in sponges is :

1. Intracellular
2. Intercellular
3. Both 1 and 2
4. None of the above.

Answer: Intercellular

Question 9. Spongocoel of leucosolenla is lined by :

1. Pinacocytes
2. Amoebocytes
3. Choanocytes
4. Scleroblasts.

Answer: 3. Choanocytes

Question 10. A common chamber for all the canals of a sponge is

1. In current canal
2. Paragastric
3. Excurrent canal
4. Radial canal.

Answer: 2. Paragastric

Question 11. Leucosolenia is :

1. Sessile, colonial and marine
2. Sessile, solitary and marine
3. Sessile, colonial and freshwater
4. Sessile, solitary and marine.

Answer: 1. Sessile, colonial and marine

Question 12. Glass rope sponge is the common name of :

1. Sycon
2. Hyalonema
3. Euspongia
4. Leucosolenia.

Answer: 2. Hyalonema

Question 13. In current canal communicates with radial canals by:

1. Apopyles
2. Prosopyle
3. Dermal Ostia
4. Gastric Ostia.

Answer: 2. Prosopyle

Question 14. Gemmules are endogenous in origin and play a vital role in:

1. Perennation
2. Dispersal
3. Reproduction
4. All of the above.

Answer: 2. Dispersal

Question 15. Mesohyal is largely secreted by :

1. Collencyte
2. Trophocyte
3. Choanocyte
4. Chromocyte.

Answer: 1. Collencyte

Question 16. In sponges, food particles are ingested by :

1. Thesocytes
2. Pinacocytes
3. Collencyte
4. Choanocytes.

Answer: 4. Choanocytes.

Question 17. Which of these cells is not found in sponges?

1. Calcoblasts
2. Myocytes
3. Porocyte
4. Cnidoblasts.

Answer: 4. Cnidoblasts.

Question 18. The power of regeneration in sponges is due to :

1. Thesocytes
2. Amoebocytes
3. Scleroblasts
4. Archaeocytes.

Answer: 4. Archaeocytes.

Question 19. Sponge differs from metazoan in :

1. Cell division
2. Division of labour
3. Cell organization
4. Sponge lacks

Answer: 3. Cell organization

Question 20. Best commercial sponges are found in :

1. Cold shallow water
2. Warm shallow water
3. Deep seawater
4. Warm shallow seawater.

Answer: 4. Warm shallow seawater.

Question 21. The skeleton of the bath sponge is made up of :

1. Calcareous spicules
2. Spongin fibres
3. Collagen fibres
4. Yellow fibres of elastic cartilage.

Answer: 2. Spongin fibres

Question 22. Sponges are not found in :

1. Sea water
2. Brackish water
3. Cold water
4. Sandy shore.

Answer: 3. Coldwater

Question 23. The course of the water system in the second is :

1. Ostia
2. In current canal
3. Prosopyle
4. Radial canal
5. Apopyle
6. Spongocoel
7. Osculum

Choose The Correct Option 

1. 1→2→3→4→5→6→7
2. 1→3→2→4→5→6→7
3. 1→4→3→4→5→6→7
4. 1→5→2→3→4→6→7

Answer: 1. 1→2→3→4→5→6→7

Question 24. Totipotent cells in sponges are :

1. Porocyte
2. Choanocyte
3. Archaeocyte
4. Pinacocyte;

Answer: 3. Archaeocyte

Question 25. Calcareous spicules are formed by :

1. Calcoblasts
2. Silicoblasts
3. Spiroblasts
4. Spongoblasts.

Answer: 1. Calcoblasts

Question 26. In a sponge body, the mesenchyme contains which type of cells:

1. Pinacocytes
2. Choanocytes
3. Amoebocytes
4. None of the above.

Answer: 3. Amoebocytes

Question 27. Monoaxon spicule with a knob at one end is called:

1. Acanthostyle
2. Tylostyle
3. Diastyle
4. Style.

Answer: 2. Tylostyle

Question 28. One of the following cells takes part in the reproduction of sponges:

1. Archaeocytes
2. Thesocytes
3. Myocytes
4. Choanocytes.

Answer: 1. Archaeocytes

Question 29. Which one of the following is the most distinctive of the character of sponges?

1. They are acellular
2. They possess special cells called choanocytes
3. They reproduce asexually
4. They are all marine.

Answer: 2. They reproduce asexually

Question 30. Which one of the following cells maintains a current of water in a sponge?

1. Trophocytes
2. Porocytes
3. Choanocytes
4. Chromocytes.

Answer: 3. Choanocytes

Question 31. The boring sponge is :

1. Spongilla
2. Euplectella
3. Cliona
4. Euspongia.

Answer: 3. Cliona

Question 32. A chamber which is common in different types of canal systems is :

1. Spongocoel
2. Coelom
3. Pseudocoelom
4. Haernocoel

Answer: 1. Spongocoel

Question 33. Osculum is generally surrounded by :

1. Spongin fibre
2. Spicules
3. Myocytes
4. Pinacocytes.

Answer: 3. Myocytes

Question 34. The cells in which the food is stored in the form of glycogen and glycoprotein are :

1. Thesocyte
2. Archaeocyte
3. Choanocyte
4. Amoebocyte

Answer: 1. Thesocyte

Question 35. The outer epithelial layer in sponges has:

1. Choanocyte
2. Amoebocyte
3. Porocyte
4. Porocyte and pinacocyte.

Answer: 4. Porocyte and pinacocyte.

Question 36. In sponges, nutrition, excretion, and respiration depend upon the system named:

1. Water vascular system
2. Canal system
3. Circulatory system
4. Haemocoelomic system.

Answer: 2. Canal system

Question 37. Which one of the sponges is harmful in the oyster industry?

1. Cliona
2. Ettspongia
3. Hyalonema
4. Euplectella.

Answer: 1. Cliona

Question 38. Olynthus is termed as the simplest type of sponge in structure as well as in form :

1. It is an adult animal belonging to the germs as suggested by Haeckel
2. A species of leucopenia
3. A transitory stage in the life history of the second
4. None of the above.

Answer: 2. A species of leucopenia

Question 39. Which cells are found only in sponges?

1. Amoeboid cells
2. Choanocytes
3. Pigment cells
4. Gland cell.

Answer: 2. Choanocytes

Question 40. Trn most simple type of canal system of porifera, water flows through which one of the following ways?

1. Ostia spongocoel – osculum + exterior
2. Spongocoel – ostia + osculum + exterior
3. Osculum – spongocoel + ostia -+ exterior
4. Osculum – ostia – spongocoel + exterior.

Answer: 3. Osculum – spongocoel + ostia -+ exterior

Question 41. Gemmules are helpful in :

1. Digestion
2. Sexual reproduction
3. Water current relation
4. Asexual reproduction.

Answer: 4. Asexual reproduction.

Question 42. Which of the following is a freshwater sponge?

1. Euplectella
2. Spongilla
3. Euspongia
4. Sycon.

Answer: 2. Spongilla

Question 43. Larva of the sponge is known as :

1. Glochidium larva
2. Trochophore larva
3. Zoea larva
4. Amphiblastula larva.

Answer: 4. Amphiblastula larva.

Question 44. Which one of the following is not a class of phylum Porifera?

1. Calcarea
2. Hexactinellida
3. Hydrozoa
4. Demospoangiae.

Answer: 3. Hydrozoa

Question 45. Protospongia is a connecting link between :

1. Protozoa and porifera
2. Porifera and coelenterata
3. Protozoa and annelida
4. None of the above.

Answer: 1. Protozoa and Porifera

Question 46. The dried piece of bath sponge is made up of :

1. Cellulose fibres
2. Silk fibres
3. Spongin fibres
4. Yellow elastic fibres.

Answer: 3. Spongin fibres

Question 47. In sponges, prostyle is a :

1. Cell at the opening of the incurrent canal
2. Smaller canal and connect incurrent canal with radial canal
3. A cell which forms the lining of spongocoel
4. Contractile element at osculum.

Answer: 2. Smaller canal and connect incurrent canal with radial canal

Question 48. Which one of the following statements is correct?

1. The body of sponges consists of epithelial tissues only
2. All 4 types of tissues are seen in the body of the sponge
3. Only epithelial and connective tissues are present
4. Structurally organized tissues are absent in the body of the sponge.

Answer: 4. Structurally organized tissues are absent in the body of a sponge.

Question 49. In an experiment, the sponge is squeezed through silk bolting cloth and allowed to stand undisturbed in an appropriate medium. It is per{ormed to prove that :

1. The sponges are multicellular
2. The cells are loosely arranged
3. The cells are so small that they can be squeezed through cloth
4. The sponges are non-living.

Answer: 2. The cells are loosely arranged

Question 50. Phylogenetically sponges have evolved from :

1. Protozoans
2. Flagellates
3. Choanoflagellates
4. Ciliates.

Answer: 3. Choanoflagellates

Question 51. The inner lining of spongocoel is formed by :

1. Porocytes
2. Pinacocytes
3. Choanocytes
4. Archeocytes.

Answer: 3. Choanocytes

Question 52. Which of the following is not diploblastic?

1. Coelenterata
2. Porifera
3. Acnidaria
4. Platyhelminthes.

Answer: 4. Platyhelminthes.

Question 53. The body of sponges is mainly composed of :

1. Spongin fibres
2. Mesogloea
3. Spicules
4. Nematoblasts

Answer: 1. Spongin fibres

Phylum Coelenterata Cnidaria Multiple Choice Questions

Question 1. Which of the following is a radially symmetrical animal?

1. Planarian
2. Rotifer
3. Fluke
4. Sea anemone.

Answer: 4. Sea anemone.

Question 2. A distinguishing feature of cnidarians is the presence of specialized cells that contain nematocysts. They are located on the surface of the body wall and tentacles. They are used for capturing prey. These cells are called:

1. Cnidocytes
2. Flame cells
3. Statocysts
4. Nephridiopores.

Answer: 1. Cnidocytes

Question 3. Scyphozoan medusae are most commonly called :

1. Sea anemones
2. Jellyfishes
3. Corals
4. Hydra.

Answer: 4. Hydra.

Question 4. The ciliated free-swimming larval stage of cnidarian Aurelia (jellyfish) is called:

1. Blastula
2. Planula
3. Polyp
4. Medusa.

Answer: 1. Blastula

Question 5. A hydra is the simplest form of nervous system for integrating the functions of the body. It is called as :

1. Ladder system
2. Nerve net system
3. Ganglionic system
4. Ventral solid cord system.

Answer: 2. Nerve net system

Question 6. Polymorphism is an occurrence of:

1. Several organ systems in an individual
2. Several patterns of adaptation in a major animal group
3. Several modes of feeding in an individual.
4. Several modes of phenotypes in a population.

Answer: 4. Several modes of phenotypes in a population.

Question 7. Coelenterata includes sedimentary animals, they are:

1. Bilaterally symmetrical, triploblastic
2. Radially symmetrical, diploblastic
3. Bilaterally symmetrical, diploblastic
4. Radially symmetrical, triploblastic.

Answer: 2. Radially symmetrical, diploblastic

Question 8. The gastrovascular cavity is divided into compartments:

1. Hydrozoa
2. Scyphozoa
3. Actinozoa
4. None of the above.

Answer: 2. Scyphozoa

Question 9. Polymorphism is exhibited by :

1. Hydra
2. Obelia
3. Aurelia
4. Coral.

Answer: 2. Obelia

Question 10. The alternation of sexual and asexual generation is known as:

1. Digenesis
2. Metagenesis
3. Metamorphosis
4. Dimorphism.

Answer: 2. Metagenesis

Question 11. Which one of the following inhabitants of freshwater bodies?

1. Hydra
2. Obelia
3. Tubularia
4. Gorgonia.

Answer: 1. Hydra

Question 12. The animal without sexual medusae is :

1. Velella
2. Millipore
3. Hydra
4. None of the above.

Answer: 3. Hydra

Question 13. Testes in Hydra:

1. Are less numerous than ovary
2. Have a conical tip
3. Are nearer the basal disc
4. Develop one sperm in each.

Answer: 2. Have a conical tip

Question 14. In an association mutually beneficial to both partners, in the green hydra, some small green plants live in it giving it a green colour. They are :

1. Zooxanthellae
2. Zoochlorella
3. Volvox
4. Chlamydomonas.

Answer: 2. Zoochlorella

Question 15. Which one of the following layers contains zoochlorella?

1. Gastrodermal cells
2. Myoepithelial cells
3. Mesogloea
4. Interstitial cells.

Answer: 1. Gastrodermal cells

Question 16. Tentacles of hydra arise from :

1. Aboral end
2. Hypostome
3. Stalk
4. Body wall.

Answer: 2. Hypostome

Question 17. In hydra between the ectodermic and gastrodermis, the intermediate structureless layer is found. This is known

1. Mesogloea
2. Muscle endothelial
3. Myoepithelial layer
4. Endoderm.

Answer: 1. Mesogloea

Question 18. Spermatogonia in hydra develops from :

1. Interstitial cells
2. Gastrodermis
3. Muscle endothelial cells
4. Gland cells.

Answer: 1. Interstitial cells

Question 19. The proximal end of hydra bears an adhesive disc which secretes a sticky substance for:

1. Protection
2. Defence from enemies
3. Sexual attraction
4. Attachrnent to the substrate of hydra.

Answer: 4. Attachrnent to the substrate of hydra.

Question 20. Which of the following will happen to a hydra when it is cut transversely into 2 halves?

1. Building up of lost parts
2. Reunion of 2 halves
3. Wound healing
4. Death.

Answer: 1. Building up of lost parts

Question 21. Below the hypostome the number of tentacles is usually:

1. 4-11
2. 10-16
3. 6-10
4. 6-16.

Answer: 3. 6-10

Question 22. When an organism can be cut into two halves by one of the many longitudinal planes passing through the centre, the symmetry is said to be:

1. Bilateral symmetry
2. Radial symmetry
3. Lateral symmetry
4. Longitudinal symmetry.

Answer: 2. Radial symmetry

Question 23. The single sac-like cavity in the body of a hydra is called :

1. Arachenteron
2. Blastocoel
3. Gastrovascular cavity
4. Hypnotoxin.

Answer: 3. Gastrovascular cavity

Question 24. The poisonous fluid present in the nematocyst of hydra is:

1. Toxin
2. Venom
3. Haematin
4. Hypnotoxin.

Answer: 3. Haematin

Question 25. In hydra, the gastrodermis is composed of :

1. Myoepithelial cells
2. Myonutritive cells
3. Sensory cells
4. Cnidoblasts.

Answer: 2. Myonutritive cells

Question 26. The mesogloea of hydra contains:

1. Nerve cells
2. Sensory cell
3. Nematoblasts
4. Nocells.

Answer: 4. Nocells.

Question 27. In hydra, the nematocysts are absent on the basal disc. They are abundant in:

1. Tupper part
2. Tmidclle part
3. Tentacles
4. None of the above.

Answer: 3. Tentacles

Question 28. Which animal depicts radial symmetry?

1. Planaria
2. Obelia
3. Earthworks
4. Pila.

Answer: 2. Obelia

Question 29. Stenotele nematocyst of hydra is important for :

1. Catching prey
2. Paralysing prey
3. Tasting the food
4. Tasting the water around;

Answer: 2. Paralysing prey

Question 30. Tentacles of hydra extend to the large length due to :

1. Relaxation of myonemes of epitheliomuscular cells
2. Relaxation of myonemes of gastrovascular cells
3. The pressure generated by the body fluid
4. None of the above.

Answer: 1. Relaxation of myonemes of epitheliomuscular cells

Question 31. The body wall of a hydra consists of :

1. Ectoderm, mesoderm and endoderm
2. Ectoderm, mesenchyme and endoderm
3. Ectoderm and endoderm
4. Epidermis, mesogloea and gastrodermis.

Answer: 4. Epidermis, mesogloea and gastrodermis

Question 32. Which one of the following is known as a persistent embryonic layer?

1. Germ cells
2. Cnidoblasts
3. Interstitial cells
4. Muscular cells.

Answer: 3. Interstitial cells

Question 33. The process of digestion of food in hydra is :

1. Intercellular
2. Extracellular
3. Intracellular
4. Both extracellular and intracellular.

Answer: 4. Both extracellular and intracellular.

Question 34. One of the following nematocysts is the most specialized for catching prey:

1. Penetrant
2. Large agglutinant
3. Small conglutinant
4. Desmoneme.

Answer: 4. Desmoneme.

Question 35. Nerve cells of hydra differ from those of higher animals in that :

1. They conduct impulses in a definite direction
2. They conduct impulses in all directions
3. Both 1 and 2
4. None of the above.

Answer: 2. Both 1 and 2

Question 36. One of the following animals has a nervous system but no brainer:

1. Cockroach
2. Earthworm
3. Hydra
4. Sponges.

Answer: 3. Hydra

Question 37. In hydra, our contains :

1. A few ova
2. Single ovum
3. No ova
4. Lunlerous ova.

Answer: 2. Single ovum

Question 38. Mark the group, of animals that do not move :

1. Bug and slug
2. Coral and sponges
3. Antedon and holothurian
4. Coral and lepisma.

Answer: 2. Coral and sponges

Question 39. Fertilization in hydra is :

1. Hxtemal
2. In the body Glendale
3. Both male and female individuals come close and fuse
4. None of the above.

Answer: 2. In the body Lenrale

Question 40. Self-fertilization in Hydra never takes place because they are :

1. Protandrous
2. Protogynous
3. Asexual
4. Hermaphrodite.

Answer: 1. Protandrous

Question 41. Hydra reproduces by bidding during:

1. Unfavourable conditions
2. Favourable conditions
3. Less water supply
4. Summer.

Answer: 2. Favourable conditions

Question 42. Coral reefs have been a result of activity of mainly:

1. Molluscs
2. Echinoderms
3. Coelenterates
4. Hernichordates.

Answer: 3. Coelenterates

Question 43. Polymorphism is best defined as the occurrence of:

1. Several types of organ systems in an individual
2. Different kinds of larval forms in the life history of an animal
3. Different functions performed by a single kind of organism
4. Several different types of individuals in the species.

Answer: 4. Several different types of individuals in the species.

Question 44. The cells of blastula in hydra divide repeatedly and tangentially forming many cells which migrate inward from all directions and fill in the blastocoel. This process is called:

1. Invagination
2. Immigration
3. Involution
4. Ingression.

Answer: 4. Ingression.

Question 45. Which animals are exceptions to the organ system level of organisation?

1. Echinoderms
2. Sponges
3. Coelenterates
4. Both 2 and 3.

Answer: 4. Both 2 and 3.

Question 46. Hydra is negatively chemotropic because it :

1. Moves away from strong light
2. Prefers weak illumination
3. Moves to water of low temperature
4. Avoids chlorinated water.

Answer: 3. Moves to water of low temperature

Question 47. If a hydra has to propagate successfully in a pond which is going to dry up soon, what method of reproduction will take place in the animal:

1. Panhenogenesis
2. Budding
3. Sexual
4. Sporogony.

Answer: 3. Sexual

Question 48. Tentaculocyst is :

1. Receptor organ in Ascaris
2. A part of Scolex
3. Protective covering of amoeba
4. A receptor organ of aurelia.

Answer: 4. A receptor organ of aurelia.

Question 49. Metagenesis is exhibited by :

1. Hydra
2. Fungia
3. Metridium
4. Obelia.

Answer: 4. Obelia.

Question 50. Penetrants and steno-teles are the names of hydra’s nematocysts. Of these;

1. Penetrants are larger
2. Penetrants are smaller
3. Steoteles are not found in hydra
4. Both are the same.

Answer: 4. Both are the same.

Question 51. A fringing reef is usually located at:

1. Very near the shore
2. In deep sea
3. In cold sea
4. Far away from the shore.

Answer: 1. Very near the shore

Question 52. True corals come from the order :

1. Hydroidea
2. Pennatulacea
3. Madreporaria
4. Alcyonacea.

Answer: 3. Madreporaria

Question 53. Sea pen is a popular name for:

1. Gorgonia
2. Pennatula
3. Fungia
4. Corallium.

Answer: 2. Pennatula

Question 54. The body cavity of cockroaches is

1. Hydrozoan
2. Scyphozoan
3. Anthozoan
4. Fish.

Answer: 3. Anthozoan

Question 55. Rhopalium is a complex of :

1. Two sense organs
2. Three sense organs
3. Four sense organs
4. Five sense organs.

Answer: 3. Four sense organs

Question 56. In obelia, statocysts function as the organ for:

1. Hearing
2. Iight perception
3. Smell
4. Equilibrium.

Answer: 4. Equilibrium.

Question 57. In hydra tests are located at:

1. Proximal half end of body
2. The distal half end of the body
3. Both the ends
4. Tentacles only.

Answer: 2. Distal half end of body

Question 58. Hydra can digest all types of food except:

1. Proteins
2. Fats
3. Sugars
4. Starch.

Answer: 4. Starch.

Question 59. Aurelia belongs to:

1. Hydrozoa
2. Scyphozoa
3. Actinozoa
4. Cephalopoda.

Answer: 2. Scyphozoa

Question 60. Which of the following phyla include diploblastic animals?

1. Coelenterata
2. Platyhelminthes
3. Aschelminthes
4. Echrnodermata.

Answer: 1. Coelenterata

Phylum Platyhelminths

Question 1. Flatworms have three tissue layers and only one body cavity-the digestive cavity. They are called:

1. Acoelomates
2. Pseudo-acoelomates
3. Pseudo-coelomates
4. Coelomates.

Answer: 1. Acoelomates

Question 2. Which of the following is an ectoparasite?

1. Fasciola
2. Paragonimus
3. Diplozoan
4. Taenia

Answer: 3. Diplozoan

Question 3. A unisexual fluke is :

1. Schistosoma
2. Paragonimus
3. Fasciola
4. Opisthorchis.

Answer: 1. Schistosoma

Question 4. Locomotory and receptor organs are lacking in :

1. Liver fluke
2. Lung fluke
3. Intestinal fluke
4. Tapeworm.

Answer: 4. Tapeworm.

Question 5. Flatwornrs have:

1. Ectothelial eggs
2. Endothelial eggs
3. Both 1 and 2
4. None of the above.

Answer: 2. Endothelial eggs

Question 6. The infective stage of taenia for man is:

1. Hexacanth
2. Onchosphere
3. Cysticercus
4. Adult worm.

Answer: 4. Adult worm.

Question 7. How many intermediate hosts does Paragonimus have?

1. One
2. Two
3. Three
4. None of the above.

Answer: 2. Two

Question 8. Paragonimus lives in :

1. Intestine
2. Blood
3. Lung
4. Brain.

Answer: 3. Lung

Question 9. For protection against the infection of diphyllobothrium, do not take raw or undercooked:

1. Pork
2. Mutton
3. Vegetables
4. Fish.

Answer: 4. Fish.

Question 10. Tapeworms do not have an alimentary canal because they get good from:

1. Suckers
2. Mouth
3. Body surface
4. All of the above.

Answer: 3. Body surface

Question 11. Which of the following statements about taenia saginata is true?

1. It has a double circle of hooks on the rostellum
2. Its life history involves pig as an intermediate host
3. It has two large hooks on the scolex
4. It has no rostellar hooks.

Answer: 1. It has a double circle of hooks on the rostellum

Question 12. The study of worms which cause a parasitic infestation in man is called :

1. Helminthology
2. Herpetology
3. Ichthyology
4. Malacology.

Answer: 1. Helminthology

Question 13. Liver fluke is :

1. Coelomate
2. Pseudo-coelomate
3. Acoelomate
4. Haemo-coelomate.

Answer: 3. Acoelomate

Question 14. Taenia attaches to the intestinal wall by:

1. Scolex
2. Suckers
3. Hooks
4. Both 2 and 3.

Answer: 4. Both 2 and 3.

Question 15. Anaerobic respiration is likely to occur in :

1. Ants
2. Eafthworm
3. Tapeworms
4. Echinoderms.

Answer: 3. Tapeworms

Question 16. The correct sequence of various larvae in the liver fluke is :

1. Miracidium→sporocysts →cercaria → redia→ metacercaria
2. Miracidium → redia → Cercaria→metacercaria → sporocyst
3. Metacercaria → cercaria → redia →sporocyst → miracidium
4. Miracidium → sporocysts →redia→cercaria -→metacercaria.

Answer: 4. Miracidium →sporocysts→ redia→ cercaria→ metacercaria.

Question 17. Food is sucked into the fasciola hepatica with the help of:

1. Oral sucker
2. Muscular pharynx
3. Ventral sucker
4. Mouth.

Answer: 2. Muscular pharynx

Question 18. From the evolutionary point of view which group is considered to be the first triploblastic?

1. Platyhelminthes
2. Annelida
3. Coelenterata
4. Nemathelminthes.

Answer: 1. Platyhelminthes

Question 19. On examining the stool of a man, it was found to contain segments of tapeworms. Trace the possible source:

1. Fish meat
2. Beef
3. Pork
4. Mutton.

Answer: 3. Pork

Question 20. Which of the following is not a class of phylum Platyhelminthes?

1. Turbellaria
2. Hydrozoa
3. Trematoda
4. Cestoda.

Answer: 2. Hydrozoa

Question 21. Cysticercosis is caused by :

1. Taenia
2. Liver fluke
3. Bladder worm
4. Rhabditid.

Answer: 3. B1adder worm

Question 22. Which of the following is not a parasitic adaptation of helminths?

1. Secretion of mucus and anti-enzyme
2. Production of a large number of eggs
3. Presence of the nervous system
4. Presence of flame cells.

Answer: 3. Presence of nervous system

Question 23. Fasciola hepatica differs from taenia solium in:

1. Having a better-developed digestive system
2. A protective cuticle
3. Mesenchyme fills up the space between ectoderm and endoderm
4. Presence of nervous system.

Answer: 1. Having a better-developed digestive system

Question 24. Special mesodermal tissue fills up the space between various organs in flatworms:

1. Parenchyma
2. Botryoidal
3. Sclerenchyma
4. Mesogloea.

Answer: 1. Parenchyma

Question 25. In platyhelminthes, vitellarium is generally found in association with:

1. Ovaries
2. Testes
3. Both the ovary and testes
4. Gut.

Answer: 1. Ovaries

Question 26. In Platyhelminthes flame cells are units of :

1. Excretory system
2. Reproductive system
3. Vascular system
4. Respiratory system.

Answer: 1. Excretory system

Question 27. One of the main characteristics of taenia solium is that it:

1. Sucks the predigested food from the host’s intestine by employing oral suckers
2. Has no mouth, alimentary canal and anus
3. Has a head, a neck and a thorax but no abdomen
4. Passes eggs which are unaffected even at the boiling temperature of water.

Answer: 2. Has no mouth, alimentary canal and anus

Question 28. Cestodes have:

1. A scolex with sucker and hooks
2. A ribbon-like body
3. Numerous proglottids
4. All the above.

Answer: 4. All the above.

Question 29. The primary host of taenia is.

1. Pig
2. Man
3. Sheep
4. Mollusc.

Answer: 2. Man

Question 30. The intermediate host of talent solium is :

1. Pig
2. Man
3. Sheep
4. Snail.

Answer: 1. Pig

Question 31. Which one of the following larvae does not belong to liver fluke?

1. Cercaria
2. Planula
3. Media
4. Miracidium.

Answer: 2. Planula

Question 32. Miracidium larva occurs in the life cycle of :

1. Liver fluke
2. Tapeworm
3. Ascaris
4. Malarial parasite.

Answer: 1. Liver fluke

Question 33. Taenia solium feeds with :

1. Oral sucker
2. Body surface
3. Rostellum
4. Ventral sucker.

Answer: 2. Body surface

Question 34. The tapeworm is :

1. Unisexual
2. Asexual
3. Bisexual
4. None of the above.

Answer: 3. Bisexual

Question 35. The head of taenia solium is called :

1. Oral sucker
2. Acetabulum
3. Scolex
4. Rostellum

Answer: 3. Scolex

Question 36. In taenia, scolex bears at the top in the middle a prominent:

1. Cup-shaped sucker
2. Head
3. Rostellum
4. Recurved hooks.

Answer: 3. Rostellum

Question 37. The adult taenia contains :

1. 500 Proglottids
2. 1000 Progloltids
3. 800-900 Proglottids
4. Only 3 proglottids.

Answer: 3. 800-900 Proglottids

Question 38. Proglottids of cestodes have :

1. Monoecious reproductive system
2. Dioecious genitalia
3. Well-developed alimentary canal
4. Ax the above.

Answer: 1. Monoecius reproductive system

Question 39. Segments of taenia proliferate from the :

1. Head
2. Neck
3. The special region of proliferation in the neck
4. Anywhere from the body.

Answer: 3. Special region of proliferation in neck

Question 44. A proglottid is called gravid proglottid when it has :

1. Both male and female reproductive units
2. Only the female reproductive unit
3. Only the male reproductive unit well well-developed
4. Branched uterus filled with fertilized eggs.

Answer: 4. Branched uterus filled with fertilized eggs.

Question 41. Liver fluke has :

1. Self-fertilization
2. Cross-fertilization
3. None of above
4. Both of the above.

Answer: 4. Both of the above.

Question 42. The body wall in tapeworm is covered by :

1. Cuticle
2. Tegument
3. Integument
4. Mucus.

Answer: 2. Tegument

Question 43. Rhabdits are present in the epidermal cells of

1. Taenia
2. Fasciola
3. Dugesia
4. Schistosoma

Answer: 3. Dugesia

Question 44. Nen ous system of flatworms is

1. Of diffuse type
2. In the form of anterior ganglia and nerve cords
3. Consists of the central and sympathetic nervous system
4. In the form of clustered ganglia.

Answer: 2. In the form of anterior ganglia and nerve cords

Question 45. The tcstes in taenia :

1. Have a single structure
2. Have bulbed structure
3. Consist of several follicles
4. Consists of a pair of branched structures.

Answer: 3. Consist of some follicles

Question 46. The ovary in taenia is :

1. Single lobed
2. Bilobed
3. Follicular
4. A pair of glandular structures.

Answer: 2. Bilobed

Question 47. In tapeworms, fertilization is affected by one of the following manners:

1. Self-fertilization
2. Fusion of gametes between two parasites
3. Fertilization between gametes of adjacent segments
4. A combination of 1 and 3.

Answer: 4. A combination of 1 and 3.

Question 48. The life cycle of taenia is :

1. Monogenetic
2. Digenetic
3. Polygenetic
4. None of the above.

Answer: 2. Digenetic

Question 49. The infective stage of taenia in pigs is :

1. Onchosphere stage
2. Hexacanth
3. Adult stage
4. None of the above.

Answer: 4. None of the above.

Question 50. Taenia saginata differs from taenia solium mainly in the absence of:

1. Scolex
2. Hooks upon scolex
3. Suckers upon scolex
4. None of the above.

Answer: 2. Hooks upon scolex

Question 51. Onchosphere is an embryo which occurs in taenia characterized by the presence of:

1. Six hooks, primary shell only
2. Six hooks, geosphere membrane and embryophore
3. Onchosphere membrane only
4. Six hooks, onchosphere membrane, embryophore and primary shell only.

Answer: 4. Six hooks, onchosphere membrane, embryophore and primary shell only.

Question 52. Cysticercus is a stage in the life history of:

1. Fasciola
2. Ascaris
3. Taenia
4. Pheretima.

Answer: 3. Taenia

Question 53. Larval forni of a trematode which penetrates a gastropod mollusc is:

1. Hexacanth
2. Media
3. Cercaria
4. Miracidium.

Answer: 4. Miracidium.

Question 54. Trematodes have :

1. A branched alimentary canal
2. A monoecious reproductive apparatus
3. Direct or indirect alimentary canal
4. All the above.

Answer: 4. All the above.

Question 55. Schistosoma is called

1. Blood fluke
2. Chinese liver t-luke
3. Lung fluke
4. Dog tapeworm.

Answer: 1. Blood fluke

Question 56. Dugesia is an exmple of

1. Cestoda
2. Turbellaria
3. Digenetic Trematoda
4. Mgogenetic trematoda.

Answer: 2. Turbellaria

Question 57. Taenia saginata is a parasite of

1. Sheep
2. Cow
3. Man and cow
4. Dog.

Answer: 3. Man and cow

Question 58. Fasciola hepatica is a parasite that lives in the:

1. Intestine of sheep
2. Liver of sheep
3. Spleen of sheep
4. Pancreas of sheep.

Answer: 2. Liver of sheep

Question 59. Strobilation is seen in :

1. Taenia
2. Fasciola
3. Dugesia
4. Digenia.

Answer: 1. Taenia

Question 60. The presence of spicules on the body wall is a characteristic of:

1. Aurelia
2. Planaria
3. Taenia
4. Fasciola.

Answer: 4. Fasciola.

Phylum Aschelminthes

Question 1. Which of the following are pseudocoelomates?

1. Trematodes
2. Nematodes
3. Cestodes
4. Archiannelida.

Answer: 2. Nematodes

Question 2. Round worms have three tissue layers, a digestive cavity and an additional cavity between the endoderm and mesoderm. They are called as:

1. Acoelomates
2. Pseudocoelomates
3. Haemocoelomates
4. Coelomates.

Answer: 2. Pseudocoelomates

Question 3. Dracunculus medinensis is a parasite of :

1. Body fluids
2. Body tissue
3. Gut
4. Lungs.

Answer: 2. Body tissue

Question 4. The common parasite of the human large intestine is:

1. Asruris
2. Trichinella
3. Enterobius
4. Ancylostoma.

Answer: 3. Enterobius

Question 5. The Epidermis of the nematode consists of :

1. Cuticle
2. Epidermis
3. Muscle layer
4. All of the above.

Answer: 4. All of the above.

Question 6. Trichinosis is caused by :

1. Trichuris
2. Trichinella
3. Ancylostoma
4. None of the above.

Answer: 2. Trichinella

Question 7. The number of cells in the various organs of the body is fixed in :

1. Flatworms
2. Segmental worms
3. Walking worms
4. Round worms.

Answer: 4. Roundworms.

Question 8. Excretory organs of hookworm are :

1. Flame cells
2. Green gland
3. Renette glands
4. Nephridia.

Answer: 3. Renette glands

Question 9. Juvenile of Ascaris undergoes moult :

1. Twice
2. Once
3. Thrice
4. Four times.

Answer: 4. Four times.

Question 10. Pinworms are found in humans:

1. Alimentary canal
2. Colon
3. Intestine
4. Lungs.

Answer: 2. Colon

Question 11. The technical name of pinworm is :

1. Trichon cell
2. Ancylostoma
3. Oxyuris
4. Microfilariae.

Answer: 3. Oxyuris

Question 12. The most dangerous parasitic roundworms of man are:

1. Pinworm
2. Hookworm
3. Whipworm
4. Guinea worm.

Answer: 2. Hook worm

Question 13. Filaria is transmitted by :

1. Tsetse fly
2. Sandfly
3. Anopheles
4. Culex.

Answer: 4. Culex.

Question 14. Which of the following groups have one or more animals which are not

1. Ascaris, taenia
2. Enterobius,wuchereria
3. Ancylostoma, dracunculus
4. Ascaris, ancyiostoma.

Answer: 1. Ascaris, taenia

Question 15. In Ascaris lumbricoides, (roundworms) the males and females can be identified externally by certain characters. This phenomenon is called

1. Polymorphism
2. Sexual dimorphism
3. Anisogamy
4. Regeneration.

Answer: 2. Sexual dimorphism

Question 16. Ascaris is a parasite found in the :

1. Stomach
2. Vermiform appendix
3. Small intestine
4. Large intestine.

Answer: 3. Small intestine

Question 17. Ln ascaris lumbricoides :

1. The male is larger than the female
2. The body cavity is a true coelom
3. The life history involves two hosts
4. None of the above.

Answer: 4. None of the above.

Question 18. In male ascaris the posterior end is :

1. Straight
2. Upturned
3. Blunt and straight
4. Curved with pineal setae protruding out.

Answer: 4. Curved with pineal setae protruding out.

Question 19. Lips of Oscars are :

1. Horny
2. Bony
3. Cartilaginous
4. None of the above.

Answer: 1. Horny

Question 20. Which of the following systems are not well-defined in nematodes?

1. Respiratory and digestive
2. Circulatory and respiratory
3. Excretory and nervous
4. Reproductive and excretory.

Answer: 2. Circulatory and respiratory

Question 21. Helminthes parasite without any intermediate host in its life cycle is:

1. Liver fluke
2. Tapeworm.
3. Filarial worm
4. Roundworm.

Answer: 4. Roundworm.

Question 22. The cuticle in Ascaris is secreted by :

1. Muscular layer
2. Epidermis
3. Syncytial epidermis
4. None of the above.

Answer: 3. Syncytial epidermis

Question 23. The lateral lines of the epidermis in Ascaris contain :

1. Excretory canal
2. Nerves
3. Oviducts
4. Spermatic ducts.

Answer: 1. Excretory canal

Question 24. The transmission of scans takes place through:

1. Air
2. Housefly
3. Contaminated food and water
4. Female anopheles.

Answer: 3. Contaminated food and water

Question 25. In Ascaris, the respiration is:

1. Anaerobic
2. Anaerobic
3. Cutaneous
4. All the above.

Answer: 2. Anaerobic

Question 26. Cuticle of ascaris is an adaptation for :

1. Growth
2. Parasitism
3. Reproduction
4. Locomotion.

Answer: 2. Parasitism

Question 27. The matrix layer of the cuticle of ascarls is :

1. Spongy in consistency
2. Formed of keratin
3. Collagen fibres
4. Formed of basement membrane.

Answer: 1. Spongy in consistency

Question 28. Musculature it ascaris is formed of :

1. Circular muscles
2. Circular and longitudinal muscles
3. A single layer of spindle-shaped cells
4. Oblique and tangential circular muscles.

Answer: 3. Single layer of spindle-shaped cells

Question 29. Locomotion in Ascaris is brought about by:

1. Circular muscles
2. Oblique muscles
3. Alternate contraction of dorsolateral and ventrolateral muscles
4. Circular and oblique muscles to counteract

Answer: 3. Alternate contraction of dorsolateral and ventrolateral muscles

Question 30. The toxins produced by Ascaris interfere in:

1. Carbohydrate metabolism
2. Protein metabolism
3. Basal metabolic rate
4. Fat metabolism.

Answer: 2. Protein metabolism

Question 31. In Ascaris, excretory organs are:

1. Excretory cell
2. Kidney
3. Nephridia
4. Flame cells.

Answer: 1. Excretory cell

Question 32. Rectum of Ascaris :

1. Consists of tall columnar cells
2. Consists of internal cuticle
3. In males opens into the cloaca
4. All the above.

Answer: 2. Consists of internal cuticle

Question 33. The total number of apertures in male and female Ascaris are

1. Two and three
2. Three and four
3. Two each
4. Two and four.

Answer: 4. Two and four.

Question 34. Sperm in Ascaris is :

1. Monoflagellate
2. Biflagellate
3. Amoeboid
4. None of the above.

Answer: 3. Amoeboid

Question 35. Female ascsris lay eggs daily at the rate of about:

1. 10
2. 10,000
3. 1,00,000
4. 2,00,000.

Answer: 4. 2,00,000.

Question 36. In states, fertilization occurs in :

1. Water
2. Intestine of man
3. Proximal part of the uterus
4. Vagina.

Answer: 3. Proximal part of uterus

Question 37. A coiled embryo within the egg shell is formed in:

1. 24 Hours
2. 5 To 8 days
3. 10 -14 Days
4. 2 To 3 days.

Answer: 3. 10 -14 Days

Question 38. The innermost layer of shells of eggs is formed of :

1. Esterified glycosides
2. Proteins
3. Carbolrydrates
4. Phospholipids.

Answer: 1. Esterified glycosides

Question 39. First stage of the ascaris larva is :

1. Juvenile
2. Rhabdite larva
3. Rhabditoid larva
4. None of the above.

Answer: 3. Rhabditoid larva

Question 40. Final moulting gin ascaris takes place in :

1. Outside the body of a man
2. Intestine of man
3. Lungs of man
4. The trachea of man.

Answer: 2. Intestine of man

Question 41. Rhabditoid larva infects man by :

1. Boring the sole of feet
2. With water
3. With air
4. With contaminated food.

Answer: 4. With contaminated food.

Question 42. The infective stage of Ascaris is :

1. 1st stage larva
2. 2nd stage larva
3. 3rd stage larva
4. Egg itself.

Answer: 2. 2nd stage larva

Question 43. In the life cycle of Ascaris 3rd moulting occurs in:

1. Intestine
2. Lung
3. Heart
4. Liver.

Answer: 3. Heart

Question 44. Sites of first, second and third moulting of Ascaris larva are :

1. Stomach, intestine and liver
2. Soil, lungs and lungs
3. Intestine, lungs and liver
4. Lungs, intestine and liver.

Answer: 2. Soil, lungs and lungs

Question 45. Ascariasis is syntonised by :

1. Abdominal discomforts
2. Headache
3. High fever
4. All the above.

Answer: 1. Abdominal discomforts

Question 46. The larva of Ascaris circulates in the body of a man:

1. Intestine-liver-trachea-lungs-intestine
2. Intestine-heart-lungs-trachea-intestine
3. Intestine-liver-heart-lungs-intestine
4. Intestine-lungs-liver-trachea-intestine

Answer: 3. Intestine-liver-heart-lungs-intestine

Question 47. Infection of which parasite often gives rise to cough

1. Tapeworm
2. Pinworm
3. Guinea worm
4. Roundworm.

Answer: 4. Roundworm.

Question 48. In,a.sihelminthes the space between the body wall and visceral organs is called:

1. Pseudocoel
2. Schizocoel
3. Hameocoal
4. Roundworm

Answer: 1. Pseudocoel

Question 49. All roundworms differ from all flatworms in having :

1. Longitudinal nerve cord
2. Segrnerited body
3. Metamorphosis in their life cycle
4. Presence of pseudocoelom.

Answer: 4. Presence of pseudocoelom.

Question 50. Special modifications of ascaris in its parasitic mode of life is:

1. Segmented body
2. Resistant cuticle
3. Tubular body
4. Presence of toothed lips

Answer: 2. Resistant cuticle

Phylum Annelids

Question 1. Segmentation is found in :

1. Annelida
2. Arthropoda
3. Vertebrata
4. All of the above.

Answer: 4. All of the above.

Question 2. Trochophore larva occurs in :

1. Anneiida
2. Mollusca
3. Brachiopoda
4. All of the above.

Answer: 4. All of the above.

Question 3. The zoological name of the paddle worm is :

1. Phererimr
2. Arenicola
3. Chaetopterus
4. Polynoe

Answer: 3. Polynoe

Question 4. Branchiae are respiratory organs in

1. Nereis
2. Aphrodite
3. Polynoe
4. All of the above.

Answer: 4. All of the above.

Question 5. Parapodia are locomolory organs in :

1. Oligochaeta
2. Polychaeta
3. Diplopoda
4. Chiropoda.

Answer: 2. Polychaeta

Question 6. Segmentation in annelids is :

1. Hornonornous
2. Heteronomous
3. Both 1 and 2
4. None of the above.

Answer: 3. Both 1 and 2

Question 7. Aphrodite is popularly called as

1. Scale worm
2. Faloloworm
3. Lugworm
4. Sea mouse.

Answer: 4. Sea mouse

Question 8. Locomotion in leeches is brought about by :

1. Parapodia
2. (Ts) setae
3. Suckers
4. Body muscles and suckers.

Answer: 4. Body muscles and suckers.

Question 9. The excretory material of leech is mainly :

1. Ammonia
2. Urea
3. Uric acid
4. Amino acids.

Answer: 1. Ammonia

Question 10. Leech is :

1. Unisexual
2. Bisexual
3. Dioecious
4. None of the above.

Answer: 2. Bisexual

Question 11. In earthworm brain is located in :

1. Prostorniurn
2. Peristomium
3. Third segment
4. Second segment

Answer: 3. Third segment

Question 12. In earthworms, coelomic fluid oozes out through the :

1. Nephridiopores
2. Nephrostome
3. Dorsai acres
4. Spermathecal pores.

Answer: 3. Dorsai acres

Question 13. Which of the following does not apply to earthworms?

1. In indirect development
2. Protandry
3. Extracellular digestion
4. Closed circulatory system.

Answer: 1. In indirect development

Question 14. Blood of nereids contains haemoglobin in

1. Plasma
2. Amoeboid corpuscles
3. Red blood corpuscles
4. Both 1 and 2.

Answer: 1. Plasma

Question 15. A coelomic cavity in earthworms is

1. Schizocoelic
2. Enterocoelic
3. Haemocoelic
4. Pseudocoeiic.

Answer: 1. Schizocoelic

Question 16. The colour of the earthworm is given by :

1. Porphyrin
2. Chromatophores
3. Vitamins
4. Lacrnoglohin.

Answer: 1. Porphyrin

Question 17. The function of dorsal pores in earthworms is:

1. Respiration
2. Elimination of waste,
3. Exudation of body fluids
4. Excretion

Answer: 3. Exudation of body fluids

Question 18. In earthworm’s body is devoid of the:

1. Cuticle
2. Setae
3. Appendages
4. Epidermis.

Answer: 3. Appendages

Question 19. Septa without aperture lies between :

1. 11/12; 12/13 And 13/14 segrnents
2. 12/13; 13/14 And 14/15 segments
3. 10/11; 14/12 and 12/13 segments
4. 9/10; 10/11 And 11/12 segments.

Answer: 4. 9/10; 10/11 And 11/12 segments.

Question 20. In earthworms, chromophil cells are found in :

1. Pharyngeal gland
2. Respiratory cell
3. Sensory cell
4. Vascular system.

Answer: 1. Pharyngeal gland

Question 21. The major role of typhiosole in the intestine of earthworms is :

1. To control the flow of blood
2. To increase the absorptive surface
3. To produce digestive enzyme
4. To kill bacteria.

Answer: 2. To increase absorptive surface

Question 22. The presence of coelom and metamerism are important characters in :

1. Helminthes
2. Arthropods
3. Annelids
4. Coeienterates.

Answer: 3. Annelids

Question 23. The cuticle of annelids is ;

1. Non-chitinous and albuminoid
2. Chitinous
3. Chitinous and albuminoid
4. Non-chitinous.

Answer: 4. Non-chitinous.

Question 24. Earthworm is composed of 120 segments and prostomium refers to

1. First segment
2. 2nd segment
3. Not a segment
4. Fart of the reproductive system.

Answer: 3. Not a segment

Question 25. Setae are present in all segments except:

1. First and last segment
2. The first segment and the clitellum
3. Cliteltum, first and anal segments
4. Clitellum and last segrnent.

Answer: 3. Cliteltum, first and anal segments

Question 26. Clitellum in earthworms includes :

1. First three segments
2. 14,15 And 16 segments
3. Last three segments
4. 19, 20 And 21 segments.

Answer: 2. 14,15 And 16 segments

Question 27. In earthworms, the clitellar region helps in the process of:

1. Copulation
2. Conformation
3. Digestion
4. Locomotion.

Answer: 2. Conformation

Question 28. Where would you find calcareous glands in heretical?

1. Oesophagus
2. Stomach
3. Rectum
4. Typhlosole.

Answer: 2. Stomach

Question 29. During locomotion of earthworms:

1. Longitudinal muscles contract first
2. Circular muscles contract first
3. Both muscles contract simultaneously
4. Both muscles relax simultaneously.

Answer: 2. Circular muscles contract first

Question 30. The animals that drifted passively by water currents are known as :

1. Pelagic
2. Planktons
3. Freshwater form
4. Benthos.

Answer: 2. Planktons

Question 31. Which of these is secreted by pharyngeal mass?

1. Albumen
2. Mucin
3. Mucin arid proteases
4. None of the above.

Answer: 3. Mucin arid proteases

Question 32. The flow of blood in a dorsal blood vessel of heretical is :

1. From in front backwards
2. From behind forward
3. In both directions
4. None of the above.

Answer: 2. From behind forward

Question 33. l-lateral hearts in heretical are situated in the following segments :

1. 12th and 13th
2. 10th and 11th
3. 7th and 9th
4. Both 1st and 3rd.

Answer: 3. 7th and 9th

Question 34. Blood glands in earthworms are situated in 4, 5 and 6 segments. These are associated with:

1. Excretion
2. Digestion
3. Secretion
4. Formation of blood corpuscles.

Answer: 4. Formation of blood corpuscles.

Question 35. Lateral oesophageal hearts in heretical are situated in the following segments :

1. 12 And 13
2. 10 And 11
3. 9 And 14
4. 7 And 9th.

Answer: 1. 12 And 13

Question 36. The blood of earthworms is :

1. Colourless
2. Pinkish
3. Bluish
4. Red.

Answer: 4. Red.

Question 37. Which of these vessels distribute the blood in the first thirteen segments :

1. Dorsal
2. Oesophageal
3. Subneural
4. Lateral.

Answer: 1. Dorsal

Question 38. The blood from the seminal vesicle of earthworm is collected by :

1. Lateral oesophageal
2. Ventral blood vessel
3. Ventro tegumentary vessel
4. Subneural vessel

Answer: 1. Lateral oesophageal

Question 39. The excretory organs in earthworms are :

1. Nephridia
2. Malpighiantubules
3. Flame cells
4. Coelomc ducts.

Answer: 1. Nephridia

Question 40. Pharyngeal nephridia of earthworms are situated in segments :

1. 4,5 And 6
2. 5,6,7
3. 3, 4 And 5
4. 6, 7, 8.

Answer: 1. 4,5 And 6

Question 41. In earthworms, mesonephric excretion takes place by:

1. Integumentary nephridia
2. Septal nephridia
3. Septal and pharyngeal nephridia
4. None of the above.

Answer: 1. Integumentary nephridia

Question 42. The pharyngeal nephridia in earthworms do not open :

1. Externally
2. Terminally
3. Internally
4. None of the above

Answer: 1. Externally

Question 43. The origin of nephridium is :

1. Germinal
2. Ectodermal
3. Mesodermal
4. Endodermal.

Answer: 2. Ectodermal

Question 44. In heretical in which segments septal nephridia are found?

1. In all the segments
2. From the 15th to the last segment
3. In the first 15 segments
4. From last to last segment.

Answer: 2. From the 15th to the last segment

Question 45. Where nephrostome is present in heretical?

1. Septal nephridia
2. Integumentary nephridia
3. Pharyngeal nephridia
4. All the above.

Answer: 1. Septal nephridia

Question 46. In earthworms, chloragogen cells perform :

1. Glycogen synthesis
2. Synthesis of urea
3. Removal of silicates
4. Elimination of surplus ca+ ions.

Answer: 2. Synthesis of urea

Question 47. How many eyes are found in heretical :

1. None
2. One
3. Two
4. Many.

Answer: 1. None

Question 48. Enteronephric nephridia throws out the excretory material:

1. Through alimentary canal
2. Through cloacal aperture
3. Directly outside
4. Through circulatory system

Answer: 1. Through alimentary canal

Question 49. In earthworms the ovary is situated in the :

1. 11th segment
2. 10Th segment
3. 13th segment
4. 14th segment.

Answer: 4. 14th segment.

Question 50. In earthworms, the testes are enclosed in the following segments :

1. 3th and 10th
2. 8Th and 9th
3. 11Th and 10th
4. 12th and 10th.

Answer: 2. 8th and 9th

Question 51. In which segment female genital aperture is found heretical?

1. 14th
2. 19th
3. 18th
4. 17th.

Answer: 4. 17th.

Question 52. In earthworms, the spermathecae are used for

1. Development of ovum
2. Development of sperms
3. Storing of spermatozoa
4. Storing oval

Answer: 3. Development of Sperms

Question 53. In earthworm the

1. Oviduct
2. Spermatheca
3. Clitellum
4. Cocoon.

Answer: 4. Trochophore

Question 54. The annelids larva if present is :

1. Tadpole
2. Planula
3. Trochophore
4. Ephyra.

Answer: 3. Trochophore

Question 55. The Polychaeta have all but one of the following characteristics :

1. Exclusively marine
2. Segmentation infinite
3. Distinct head
4. Setae are numerous throughout the body.

Answer: 1. Exclusively marine

Question 56. The term deuterostomes excludes :

1. Vertebrata
2. Echinoderamta
3. Cephalochordata
4. Annelida.

Answer: 4. Vertebrata

Question 57. Which statement is not correct for septal nephridia of heretical?

1. These occur in all segments except the first fourteen
2. They are enteronephric
3. They have a complicated nephrostome
4. They are exonephric.

Answer: 4. They are exonephric.

Question 58. Which has not been correctly classified

1. Oli go chaeta-heretical
2. Archiannelida-glossophobia
3. Hirudinea-pontobdella
4. Polychaeta-series

Answer: 2. Archiannelida-glossophobia

Question 59. Copulation occurs between two earthworms :

1. Generally at night during the rainy season
2. Generally at day time during the rainy season
3. At night during the winter season
4. At night during the summer season.

Answer: 1. Generally at night during the rainy season

Question 60. The difference between septal and pharyngeal nephridia in earthworms relates to:

1. Straight lobe
2. Vesicle
3. Funnel
4. Mode of action.

Answer: 3. Funnel

Question 61. The neurons in earthworms are :

1. Motor
2. Sensory
3. Adjustor
4. Motor, sensory and adjustor.

Answer: 4. Motor, sensory and adjustor.

Question 62. Septal nephridia are :

1. Largest in size
2. Double the size of integumentary nephridia
3. Both 1 and 2
4. Smallest in size.

Answer: 3. Both 1 and 2

Question 63. The total number of pores in the body wall of heretical, which are concerned with reproduction is :

1. 7
2. 11
3. 13
4. 14.

Answer: 3. 13

Question 64. Which is correct about earthworms?

1. It has a brain but no head
2. It has locomotory organs
3. It secretes cocoon around unfertilized egg
4. It can crawl on a smooth surface easily.

Answer: 2. It has locomotory organs

Question 65. Earthworms are:

1. Harmful to man
2. Useful to man
3. Both useful and harmful to man
4. Found only near banks of river.

Answer: 1. Harmful to man

Question 66. Hirudin, an enzyme in the saliva of leech

1. Coagulation of blood
2. Excretion
3. Sucking the blood
4. Digestion of blood.

Answer: 3. Sucking the blood

Question 67. In which area there is a hydrostatic support system?

1. Insects
2. Earthworm
3. Snail
4. Jelly lish.

Answer: 2. Earthworm

Phylum-Arthropoda

Question 1. Which of the following is not an arthropod characteristic?

1. Jointed appendages
2. Unsegmented body
3. Periodic moulting
4. Artiithted exoskeleton.

Answer: 2. Unsegmented body

Question 2. Which of the following arthropods are not manipulated?

1. Insects
2. Crab
3. Stumps
4. Spider.

Answer: 4. Spider.

Question 3. Lobster, crayfish and cancer &re

1. Myriapods
2. Crustaceans
3. Arachnids
4. Insects.

Answer: 2. Crustaceans

Question 4. Which of the following is not a characteristic of insects?

1. Three body divisions
2. Three pairs of jointed legs
3. Two pairs of antennae
4. Excretion by malpighian tubule.

Answer: 3. Two pairs of antennae

Question 5. Which of the following arthropods is a chelicerate?

1. Horseshoe crab
2. Lobster
3. Millipede
4. Grasshopper.

Answer: 1. Horse-shoe crab

Question 6. Which of the following animals does not have a hydrostatic support system?

1. Insects
2. Earthworm
3. Snail
4. Jellyfish.

Answer: 1. Insects

Question 7. Mouthparts of butterflies are :

1. Siphoninc
2. Chewing
3. Chewing lapping
4. Sponging.

Answer: 1. Siphoninc

Question 8. Wriggler is the larva of :

1. Housefly
2. Butterfly
3. Moth
4. Mosquito.

Answer: 3. Moth

Question 9. Which of the following is a social insect?

1. Butterfly
2. Moth
3. Wasp
4. Locust.

Answer: 3. Wasp

Question 10. The body cavity of an arthropod is :

1. Coelorn
2. Haemocoel
3. Spongocoel
4. Pseudocoel.

Answer: 2. Haemocoel

Question 11. Drones in honeybee are :

1. Fertile males
2. Fertile females
3. Sterile males
4. Sterile females.

Answer: 1. Lertile males

Question 12. The arthropod with a sting at the hind end is :

1. Scorpion
2. Periplaneta
3. Mantis
4. Spider.

Answer: 1. Scorpion

Question 13. Millipede belongs to the class :

1. Chilopoda
2. Diplopoda
3. Arachnida
4. Gastropoda

Answer: 2. Diplopoda

MCQs on Porifera Question 14. Which of the following has raptorial proleg?

1. Locust
2. Praying mantis
3. Wasp
4. Bed bug.

Answer: 2. Praying mantis

Question 15. Excretory organs of crustaceans are :

1. Nephridia
2. Malpighian tubules
3. Green glands
4. Flame cells.

Answer: 3. Green glands

Question 16. Cockroach is :

1. Ammonotelic
2. Uricotelic
3. Ureotelic
4. Aminotelic.

Answer: 2. Uricotelic

Question 17. Which of the underlying causes plague :

1. Salmonella Typhimurium
2. Tric hine llaspiralis
3. Yersinia pestis
4. Leishmania donovani.

Answer: 3. Yersinia pestis

Question 18. In silkworm silk is a product of :

1. Salivary glands of the larva
2. Cuticle of adult
3. Cuticle of larva
4. Salivary glands of the adult.

Answer: 1. Salivary glands of the larva

Question 19. Earthworms and cockroaches have one thing in common:

1. Ventral nerve bord
2. Closed blood vascular system
3. Nephridia
4. Trachea.

Answer: 1. Ventral nerve bord

Question 20. In insects compound eyes are composed of :

1. Ocelli
2. Ommatidia
3. Fye spots
4. Haematochrome.

Answer: 2. Ommatidia

Phylum Porifera Recommended MCQs NEET Questions Question 21. Scorpion respires with the help of :

1. Gills
2. Book lungs
3. Trachea
4. Malpighian tubules.

Answer: 2. Book lungs

Question 22. Drones in the colony of honey bees are produced by:

1. Parthenogenesis
2. Parthenocarpy
3. Zygote
4. None of the above.

Answer: 1. Parthenogenesis

Question 23. The male cricket produces a chirping sound with the help of its:

1. Vocal cords
2. Pharynx
3. Legs
4. Wings.

Answer: 3. Legs

Question 24. Locusts are closely related to :

1. Moth
2. Beetles
3. Butterflies
4. Grasshopper.

Answer: 4. Grasshopper.

Question 25. The larvae of sacculina are known as :

1. Tornaria
2. Nauplius
3. Trochophore
4. Veliger.

Answer: 2. Nauplius

Question 26. Which of these is an insect?

1. Tick
2. Mite
3. Spider
4. Lepisma.

Answer: 4. Lepisma.

Question 27. The number of segments in centipede is about :

1. 300
2. S0
3. 10-30
4. 10-25.

Answer: 4. 10-25.

Phylum Porifera Recommended MCQs NEET Questions Question 28. One of the following traits which is not found in arthropods :

1. Jointed feet
2. Segmented body
3. Movable jaws
4. Closed circulation.

Answer: 4. Closed circulation.

Question 29. Theropods include animals with jointed legs, they have a body cavity called :

1. Coelorn
2. Haemocoel
3. Gastrovascular cavity
4. Pseudocoel.

Answer: 2. Haemocoel

Question 30. The crustacean biramous appendages have a basal part is known as :

1. Exopodite
2. Epipodite
3. Protopodite
4. Endopodite.

Answer: 3. Protopodite

Question 31. Mites are closely related to :

1. Scorpions
2. Cyclops
3. Aphids
4. Beetles.

Answer: 1. Scorpions

Question 32. The first antennal segment is known as :

1. Frons
2. Pedicel
3. Scape
4. None of the above.

Answer: 3. Scape

Question 33. Antennae are absent in :

1. Dragon fly
2. Spider
3. Prawn
4. Peripatus.

Answer: 2. Spider

Question 34. Which of the following two parts in a cockroach are fundamentally similar in structure :

1. Mandible and antenna
2. Wings and anal cerci
3. Anal style and labrum
4. Maxilla and labium.

Answer: 4. Maxilla and labium.

Phylum Porifera MCQ Questions With Answers  Question 35. In Periplaneta, the number of spiracles is :

1. Six pairs
2. Eight pairs
3. Ten pairs
4. Twelve pairs.

Answer: 3. Ten pairs

Question 36. It feriplaneta the sclerites which surround the genital aperture are termed :

1. Conophores
2. Genitals
3. Gonapophyses
4. Sterna.

Answer: 3. Gonapophyses

Question 37. In cockroaches the exoskeleton is made of :

1. Calcium carbonate
2. Calcium phosphate
3. Chitinous cuticle
4. Calcium sulphate.

Answer: 3. Chitinous cuticle

Question 38. A dorsal plate of the cockroach is :

1. Pleuron
2. Plastron
3. Tergum
4. Stemum.

Answer: 3. Tergum

Question 39. Glossa and paraglossa are collectively termed as:

1. Lingua
2. Ligula
3. Labium
4. Labrum.

Answer: 2. Ligula

Phylum Porifera MCQ Questions With Answers  Question 40. Anal cerci are present :

1. Only in male Ascaris
2. Only in rare cockroaches
3. Only in female cockroaches
4. In both male and female cockroaches.

Answer: 4. In both male and female cockroaches.

Question 41. The flagellum of the antenna of a cockroach is :

1. 11 jointed
2. 13 Segmented
3. Unjointed
4. Many jointed.

Answer: 4. Many jointed.

Question 42. In cockroach antennae function as :

1. Thigmoreceptors, sensitive to touch
2. To help in catching insects
3. Locomotory structures
4. Feeding structures.

Answer: 1. Thigmoreceptors, sensitive to touch

Question 43. The chitinous endoskeleton in the head of the cockroach is known as :

1. Apodeme
2. Tentorium
3. Crematorium
4. Notatum.

Answer: 2. Tentorium

Question 44. Wings of. cockroaches are attached to anterolateral corners of terga of :

1. Mesothorax
2. Metathorax
3. Prothorax
4. Mesothorax and metathorax.

Answer: 4. Mesothorax and metathorax.

Question 45. Which one of the following characters of the forewing of the cockroach is wrong :

1. Leathery
2. Without veins
3. Opaque
4. Protective.

Answer: 2. Without veins

Question 46. Clypeus is a part of :

1. Head
2. Wing
3. Abdomen
4. Leg.

Answer: 4. Leg.

Phylum Porifera Animal Kingdom NEET Practice Question 47. For an insect feeding on body fluids, blood of the prey, the mouth parts should be of :

1. Sucking type
2. Sponging type
3. Piercing and sucking type
4. Biting type.

Answer: 3. Piercing and sucking type

Question 48. From the feeding habits, cockroaches could be classified as:

1. Herbivore
2. Carnivore
3. Frugivore
4. Omnivore.

Answer: 4. Omnivore.

Question 49. The mouth parts of cockroach are :

1. Piercing type
2. Sponging type
3. Siphoning type
4. Cutting and biting type.

Answer: 4. Cutting and biting type.

Question 50. Hepatic caecal in cockroaches is derived from :

1. Ileum
2. Midgut
3. Oesophagus
4. Crop.

Answer: 2. Midgut

Question 51. Which part of the digestive system secretes the peritrophic membrane around the food in cockroaches?

1. Crop
2. Gizzard
3. Hepatic caeca
4. Stomodaeal valve.

Answer: 4. Stomodaeal valve.

Question 52. What will happen if a peritrophic membrane is not formed in cockroaches?

1. Digestion of food will stop
2. Absorption of food will stop
3. Midgut will be injured
4. None of the above.

Answer: 3. Midgut will be injured

Question 53. In cockroach, the term regurgitation is associated with :

1. Swallowing
2. Ingestion
3. Egestion
4. Absorption.

Answer: 4. Absorption.

Phylum Porifera Animal Kingdom NEET Practice Question 54. The body cavity of a cockroach is :

1. Coelom
2. Haemocoel
3. Coelenteron
4. Pseudocoel.

Answer: 2. Haemocoel

Question 55. The blood of cockroaches is white due to :

1. Absence of haemoglobin
2. The circulatory system is open
3. There are no salts in the blood
4. There is more water in the blood.

Answer: 1. Absence of haemoglobin

Question 56. The tubular heart of a cockroach is composed of :

1. 7 Chambers
2. 9 Chambers
3. 13 Chambers
4. 14 Chambers.

Answer: 3. 13 Chambers

Question 57. What is the name of the Blood cells in Periplaneta americana?

1. Erythrocytes
2. Leucocytes
3. Haemocytes
4. Amoebocytes.

Answer: 3. Haemocytes

Question 58. The respiratory passage in cockroaches during inspiration is:

1. Spiracle and trachea
2. Longitudinal respiratory tube
3. Air chamber
4. Stigmata.

Answer: 1. Spiracle and trachea

Question 59. Oxygen is transported in cockroaches by :

1. Blood
2. Lymph
3. Trachea
4. Spiracle.

Answer: 3. Trachea

Question 60. Tracheae are supported by chitinous rings :

1. Inside the epithelium
2. Outside the epithelium
3. In between two epithelial layers
4. Both inside and around the epithelial.

Answer: 1. Inside the epithelium

Question 61. The nervous system of an insect consists of :

1. Sympathetic
2. Autonomous
3. Central, peripheral and sympathetic
4. Simple nerve cells.

Answer: 3. Central, peripheral and sympathetic