• Biotechnology And Its Applications Notes
• Basic Features Of Development Notes
• Growth, Repair Regeneration Ageing And Death Notes
• Kingdom Monera Notes
• Origin Of Life Notes
• Evidence Of Evolution Relationship Among Organisms Notes
• Theory Of Evolution By Natural Selection Notes
• Nervous System Notes
• Evolution Of Man Notes
• Human Health And Common Human Diseases (Understanding Diseases And Immune System) Notes
• Drugs And Drug Dependence Mental Health Growth Of Human Populations Notes
• Tools And Techniques Notes
• Growth And Development Notes
• Strategies For Enhancement In Food Production Animal Sources Notes
• Muscular System Notes
• Sense Organs Notes
• Skeletal Muscles Notes

• Elements Of Heredity And Variations Notes
• Strategies For Enhancement In Food Production Plant Sources Notes
• Cell Reproduction Notes
• Biomolecules Notes
• Microbes In Human Welfare And Biofertilizers Notes
• Morphology Of Plants Notes
• Chromosomal Basic Of Inheritance Genes And Chromosomes Notes
• Nature Of Gene Notes
• Biomedical Technologies Notes
• Inflorescence And Flower Notes
• Bioenergy Notes
• Gene Expression And Gene Regulation Notes
• Fruits Notes
• Enzymes Notes
• Biomembranes And Cell Wall Notes
• Cell Unit Of Lift And Structural Organization Notes
• Plant Anatomy Notes
• Morphology Of Animals Notes
• Animal Tissues Notes
• Endocrine System Notes
• Ecosystem Notes
• Gymnosperms Notes
• Phylum Chordata  Notes
• Five Kingdoms Classification Notes
• Taxonomy Of Angiosperms Notes
• Nature and Scope of Biology Notes
• Reproductive Health Notes
• Biodiversity and Wildlife Conservation Notes
• Environmental Issues Notes
• Principles And Processes Of Biotechnology Notes
• Organisms and Populations Notes
• Animal Nutrition and Digestive System Notes
• Respiration In Plants Notes
• Mineral Nutrition In Plants Notes
• Photosynthesis And Translocation Of Organic Solutes Notes
• Pteridophyta Notes
• Plant Kingdom Bryophyta Notes
• Kingdom Fungi Notes
• Kingdom Protista Notes
• The Living World Notes
• Homeostasis and Osmoregulation Notes
• Respiratory System In Animals Notes
• Reproductive System in Animals Notes
• Sexual Reproduction in Flowering Plants Notes
• Blood Circulatory System in Animals Notes
• Plant kingdom Notes
• The Living World Nature And Scope Of Biology Notes
• Plant Water Relation Water Relations Of A Cell Notes
• Nature and Scope of Biology Notes

NEET Biology Endocrine System

Hormone (Gk: Hormoein = to excite) is the secretion of the endocrine (Gk. yendon = inside, Krinein = to separate) gland.

• Endocrine Glands. (The Greek word Rendon means inside, and kinesin means to separate) These are endogenously located glands that lack the ducts (so also called ductless glands) and generally secrete their secretions into the blood (so-called glands of internal secretion) for their transportation to target organs (sites of action). Exocrine glands. Secretions of these glands are transported by duct or ductules or directly.
• Heterocrine glands are composed of exocrine and endocrine tissues. The former sends its secretion or product through a duct and the latter discharges its secretion directly into the blood For example. pancreas, gonads.
• The blood contains all the hormones but target organs pick up the required hormones only and ignore all others because target cells have a specific protein called a receptor which has a specific affinity for a particular hormone.
• In man, there are the following endocrine glands: Thyroid, Parathyroid, Thymus, Pituitary, Adrenal, Pineal body, and (pancreas, stomach, intestine, skin, kidney, and gonads mixed glands).

Read and Learn More NEET Biology Notes

NEET Biology Endocrine System Types Of Hormones With Their Function Intracellular Receptors

• The steroid and thyroid hormones enter the cell directly and bind to the intracellular receptor proteins in the cytoplasm, this complex enters the nucleus and binds to the specific regulatory sites on the chromosome. This alters the pattern of gene expression initiating its transcription, formation of specific mRNA, and then protein (enzyme).
• Synergic hormone. A pair of hormones work together for a particular function. For example. LH and FSH work together for the maturation of Graafian follicles.
• Antagonistic hormone. A pair of hormones each with opposite function. For example. Insulin and glucagon. Insulin acts as a hypoglycemic factor but glucagon acts as a hyperglycemic factor,
• Tropic hormone. A hormone of one gland activates the secretion of the hormone of another gland. For example.TSH of the anterior lobe of the pituitary gland activates the thyroid gland to secrete thyroxine.
• Chalones. These substances inhibit the secretion of other glands. For example, enterogasterone from duodenal mucosa inhibits the secretion of HCI in the gastric juice of the stomach.

Endocrine System Notes For Neet

NEET Biology Endocrine System Mechanism Of Hormone Action

Hormones are transported by the bloodstream to the entire body, but they influence only specific cells.

• Cells that respond to a certain hormone possess receptor sites for that hormone. This resembles a lock and key mechanism.
• Should the key be compatible with the lock, the door will unlock. If a hormone binds to the receptor location, an effect will ensue.
• All cells possessing receptor sites for a specific hormone constitute the target tissue for that hormone. In certain instances, the target tissue is confined to a specific gland or organ.
• In other instances, the target tissue is dispersed and disseminated throughout the body, resulting in many locations being impacted. Hormones exert their distinctive impacts on target cells by altering cellular functions.

Proteins, peptides, and modified amino acids

1. These hydrophilic (and mostly large) hormone molecules bind to receptors on the sur¬face of ‘ ‘target’ ’ cells: that is, cells able to the presence of the hormone. The receptors are transmembrane proteins. Binding of the hormone to its receptor initiates a sequence of intracellular signals that may :
2. alter the behavior of the cell (such as by opening or closing membrane channels) or stimulate (or repress) gene expression in the nucleus by turning on (or off) the promoters and enhancing the action of the genes.
3. The hormone binds to a site on the extracellular portion of the receptor.
4. The receptors are transmembrane proteins.
5. Many (but not all) pass through the plasma membrane 7 times, with their N-terminal exposed at the exterior of the cell and their C-terminal projecting into the cytoplasm.
6. Binding of the hormone to the receptor
7. Activates a G protein associated with the cytoplasmic C-terminal
8. This initiates the production of a “second messenger”. The most common of these are
9. cyclic AMP, (cAMP) which is produced by adenyl cyclase from ATP and
10. inositol 1,4, 5-triphosphate (IP₃)
11. The second messenger, in turn, initiates a series of intracellular events such as
12. phosphorylation and activation of enzymes
13. release of Ca_2⁺ stores within the cytoplasm
14. In the case of cAMP, these enzymatic changes activate the transcription factor CREB (cAMP response element binding protein)
15. Bound to its response element 5′ TGACGTCA 3′ in the promoter of genes that can respond to the hormone, activated CREB turns on gene transcription.
16. The cell begins to produce the appropriate gene products in response to the hormonal signal it has received at its surface.

NEET Biology Endocrine System Steroid Hormones

1. Steroid hormones, being hydrophobic molecules, diffuse freely into all cells. However, their “target” cells contain cytoplasmic and/or nuclear proteins that serve as receptors of the hormone.
2. The hormone binds to the receptor and the complex binds to hormone response elements – stretches of DNA within the promoters of genes responsive to the hormone. The hormone/receptor complex acts as a transcription factor turning the target gene “on” (or “off”). mRNA is formed and with translation, protein is synthesized. This protein formed is responsible for the biological action of that steroid.

NEET Biology Endocrine System Thyroid Gland

1. Discovered by Wharton (1908) it is the largest endocrine gland (3 – 7 cm in diameter and 15-20 gm in weight).
2. Situated below the thyroid cartilage of the larynx it is a bilobed structure, connected by an isthmus.
3. The only endodermal gland homologous to the endostyle of protochordate develops as a venial outgrowth from the pharyngeal wall.
4. Consists of many follicles formed by follicular cells as epithelial parts and interfollicular stroma of areolar connective tissue with parafollicular cells.

Hormones And Their Functions NEET Biology

NEET Biology Endocrine System Parathyroid Gland

Follicular cells are of two types.

1. Chief cells. The main secretory cells and Oxyntic cells with eosinophilic granules.
2. It secretes Parathormone (PTH or Collip’s hormone), a polypeptide with 84 amino acids which regulate the metabolism of calcium and phosphate;
3. Increase plasma Ca⁺⁺ level by increasing bone dissolution (osteoclastic activity) and enhancing reabsorption through renal tubules and by increasing Ca⁺⁺ absorption in the gut.
4. Thus, the maintenance of proper Ca⁺⁺ levels in the body is the synergistic effect of calcitonin, PTH, and Vit. D.
5. Increases phosphate elimination in urine and consequently lower phosphate concentration in plasma.

NEET Biology Endocrine System Adrenal Gland (OR Suprarenal body)

1. A small, yellowish-brown, paired gland situated at the anterior end of each kidney like a cap, is a semicircular structure weighing 3.5 – 4.5 gm (in adults).
2. Covered by a fibrous connective tissue capsule. The structure is internally differentiated as the outer mesodermal cortex and inner ectodermal medulla of nervous origin.
3. Cortex. The thick layer constitutes 70 – 75% part of the gland distinct into the following three zones of cells :
4. Zona glomerulosa. The outermost layer below the capsule, is made of five layers of small cuboidal basophilic cells densely set along an axis parallel to the surface.
5. Zona fasciculata. The thickest and middle parts have large polyhedral cells arranged in radiating columns perpendicular to the surface.
6. Zona reticularis. The innermost part has cells arranged in a layer to form a network.
7. Medulla. Consists of groups of round granulated cells which are modified postganglionic cells of the sympathetic nervous system having an exclusively secretory function. These are chromaffin cells, distinct in two layers :
8. Zona compactum. Densely packed rounded cells with thick plasma membrane, without any intercellular spaces, the average size of cells is 190 – 210 pm (diameter).
9. Zona spongiosum. The innermost layer of irregular cells in 5 – 12 layers with large intermolecular spaces with matrix and blood vessels, the average size of cells is 260 pm- 360 pm.

NEET Biology Endocrine System Cortical hormones

About 50 types of steroids have been isolated from the adrenal cortex hence called corticosteroids. But, only a few are biologically active, of the following 3 types.

NEET Biology Endocrine System Mineralocorticoid (Aldosterone)

• A 21-carbon steroid molecule is secreted by zona glomerulosa.
• Increases the reabsorption of Na⁺ and Cl^– by uriniferous tubules, also controls the level of other salts, and thus plays a role in osmoregulation.
• Increase the removal of K⁺ in urine.

NEET Biology Endocrine System Glucocorticoid (Cortisol or hydrocortisone and Corticosterone)

1. A steroid of 20 carbons it is secreted from zona fasciculata and zona reticularis.
2. It controls the metabolism of fat and amino acids into carbohydrates, protein, and fat, and stimulates gastric secretions.
3. Stimulates the conversion of fat and amino acids into carbohydrates (gluconeogenesis).
4. Reduces amino acid levels in tissues, and increases ketone formation in the blood.
5. Anti-inflammatory in nature suppresses the WBC movement but increases RBC count.
6. Immunosuppressive in nature, hence used for treatment of allergy and in transplantation surgery.
7. Dexotes synthesis of collagen, hence cortisole is used for treatment of arthritis or rheumatism.

NEET Biology Endocrine System Sex Corticoid

1. Secreted by zona fasciculata and zona reticularis is a 12 carbon steroid.
2. Influences sex-related changes in muscles on bone, maintains the normal growth of external sex organs, hair growth, etc., in the pre-puberty stage, and also influences sexual behavior.
3. Hypersecretion of this hormone causes gynecomastia in males with female-like characteristics like overgrowth of the mammary gland.
4. Hirsutism (Adrenal Virilism) in females: growth of facial hairs, temporal baldness, enlargement of the clitoris, atrophy of breast, hoarse voice, etc.
5. Control of Secretion. ACTH from the pituitary maintains its growth and secretion which in turn is controlled by corticotropin-releasing hormone (CRH) from the hypothalamus. Secretion of aldosterone is mainly controlled by the renin-angiotensin system.

NEET Biology Endocrine System Hormones Of Adrenal Medulla

1. Medullary hormones are formed from the amino acid tyrosine.
2. Chromaffin cells take up tyrosine which is first hydroxylated and then decarboxylated to form dopamine which is further hydroxylated to form noradrenaline, this is then methylated to form adrenaline.
3. All these, dopamine, noradrenaline, and adrenaline together are called catecholamines which means “catch-all” Adrenaline (or Epinephrine)
4. Its secretion (from zona compactum) is stimulated by emergency conditions like fear, anger, accident, injury, stress, etc. hence is also called an emergency hormone. Its effect is like a sympathetic nervous system.
5. Norepinephrine (or Noradrenaline).
6. Secreted from zona spongiosus it is a polypeptide.
7. It is a vasoconstrictor that increases blood pressure (both systolic and diastolic) and controls the normal circulation of blood.
8. Control of Adrenal Medulla.
9. Its secretion is controlled by the sympathetic (autonomic) nervous system and feedback system through the level of adrenaline and nor-adrenaline in the blood.

Pituitary Gland Hormones NEET Study Material

NEET Biology Endocrine System Thymus Gland

1. It is a single, bilobed, flattened, pyramidal gland, situated in the mediastinal space just in front of the heart.
2. Grows at an early age and becomes fully developed at 16 years but starts degenerating after 18 years and atrophies after the age of 25 years.
3. It is partly endocrine and partly lymphoid, covered by a connective tissue capsule, and consists of two zones: (i) Outer cortex with lymphocyte-like cells; and
4. Inner medulla comprising reticular cells. Thymosin is the only hormone secreted from this gland with the following functions :
5. Stimulates T-lymphocytes to counter the attack of pathogens and antigens.
6. Helps in the development of sex glands.
7. Controls the heartbeat through the S.A. node.

NEET Biology Endocrine System Pineal Body

1. Situated on the roof of 3rd ventricle (diencephalon), covered by a capsule from which many septa (or trabeculae extend inside dividing it into many lobules; contain 2 types of cells :
2. Parenchymal pinealocytes with minute processes; neuroglia with the darkly stained nucleus.
3. A few acervuli or brain sand are present within the capsule.

NEET Biology Endocrine System Hypothalamus

1. It is the floor of the diencephalon (forebrain) with many neurosecretory cells that secrete a variety of hormones to control the secretion of the pituitary gland.
2. It also contains several such nerve cells whose axons terminate into the posterior pituitary and secrete hormones.
3. The ability of endocrine secretion in the hypothalamus is to monitor metabolite and hormone levels in the body as per the information gathered by the brain. Hypothalamic hormones released in the blood come to the pituitary through hypothalamo-hypophyseal portal circulation.
4. These include various releasing and inhibiting hormones as follows :
5. Hypothalamic hormones Influence hormones of the pituitary

NEET Biology Endocrine System Pituitary Gland (Hypophysis)

• Located on the ventral aspect of the hypothalamus, this single pea-sized gland was historically regarded as the master gland (Vesalius) because to its regulatory influence over all endocrine glands. However, Webster (1967) rejected this notion.
• It is now referred to as the conductor of an endocrine orchestra.
• Situated in a cavity known as the sella turcica, at the base of the sphenoid bone, it is linked via a stalk termed the infundibulum to the hypothalamus.
• This stalk is lacking in mammals.

Pituitary Gland Hormones NEET Study Material

NEET Biology Endocrine System Hormones Of the Posterior Lobe Of the Pituitary Gland

Antidiuretic hormone (ADH or Vasopressin or Pitressin)

1. The osmoregulation hormone controls the volume of urine by increasing water reabsorption in nephric tubules.
2. Brings back the normalcy in the autonomic nervous system during periods of stress, pain, anger, and excitement.
3. Deficiency of its level causes ‘diabetes insipidus’ (drinking disease), an abnormal amount of water is lost in the urine and to compensate for it the patients keep taking equally high amounts of water.

Oxytocin (or Pitocin or labor hormone or birth hormone)

1. Secreted from median eminence of pars nervosa hence is the direct secretion of hypothalamus stored in the pituitary.
2. Facilitates childbirth by loosening pubic symphysis before the birth of the child causing contraction and relaxation of muscles of the uterus, relaxing vaginal muscles and vestibular sphincter of the vulva
3. The release of milk from the mammary gland is made by relaxing the muscles of the nipple.

NEET Biology Endocrine System Islets Of Langerhans (Pancreas)

1. The pancreas acts as both an exocrine and endocrine gland and hence is referred to as a heterochrony gland
2. The endocrine component of the pancreas Islets of Langerhans was discovered by Langerhans (1950).

NEET Biology Endocrine System Hormones Of Islets Of Langerhans

NEET Biology Endocrine System Insulin

• Isolated by Banting and Best and its primary structure was determined by Sanger(1950).
• Hypersecretion causes hypoglycemia(extreme case insulin shock)

NEET Biology Endocrine System Glucagon

1. Discovered by Kimbell and Murlin (1935) a polypeptide with a molecular weight of 2495; comprises 29 amino acids in a single chain.
2. Hyperglycemic, by enhancing glycogenolysis in the liver.
3. Promotes gluconeogenesis, uptake of amino acids, and its deamination in the liver.
4. Lowers blood calcium level by increasing its renal elimination.
5. It does not affect muscle glycogen.
6. Its hypersecretion causes diabetes mellitus.

NEET Biology Endocrine System Somatostatin

• Secreted from 8 cells, also called a GHH balances the level of glucagon and insulin as per requirement of the body.

NEET Biology Endocrine System GONADS

• Gonads also secrete a variety of hormones.

NEET Biology Endocrine System Testes

1. The interstitial cells (or cells of Leydig) in the stroma secrete androgen (steroid) from which the male sex hormone testosterone is synthesized.
2. Induces the production of male gametes (sperms) and their morphogenesis.
3. Promotes growth and virility of skeleton muscle, external genitalia (accessory sex organs) secondary sex characters in puberty.
4. Its hyposecretion causes eunuchoidism, with the following symptoms.
5. Less growth of secondary sex organs (prostate, seminal vesicle, penis)
6. Improper spermatogenesis (infertility) and loss of secondary sexual characters.
7. Extreme hyposecretion causes complete sterility.
8. Sertoli cells secrete inhibin hormone that inhibits sperm formation.

Pituitary Gland Hormones NEET Study Material

NEET Biology Endocrine System Ovaries

1. Follicular cells and theca of maturing follicles secrete estrogen (17 (J-estradiol), a steroid.
2. Stimulates production, growth, and maturation of ovum and functions of secondary sex organs (uterus, fallopian tube, and ducts of mammary glands).
3. Maintains external or secondary sexual characters.
4. FSH from the anterior pituitary controls the level and functions of estrogen.
5. The corpus luteum formed from a ruptured follicle after ovulation secretes another hormone progesterone (a steroid) the pregnancy hormone.
6. Helps in the thickening of the uterus wall (endometrium) increasing blood supply to restore normalcy after menstruation.
7. Implantation of zygote on uterus wall, and formation of placenta.
8. Maintains the level of dissolved 0₂ in the embryonic fluid.
9. It also secretes inhibin hormone that stops follicular maturation.

NEET Biology Endocrine System Memory Points

1. Thyroidectomy – removal of thyroid gland.
2. Hypophysectomy- removal of the entire pituitary gland.
3. Pheromones (Ectohormones). These are intraspecific chemical messengers released by an animal into the air to initiate specific responses in another animal of the same species. These may be signals of food, mate, etc. The term pheromone was coined by Karlson and Butenandt (1959). The first known pheromone is bombycol.
4. Synthetic oxytocin is administered to induce uterine contraction in a woman who is exhausted during delivery. It is also administered in female cattle to induce lactation.
5. Feedback inhibition. In this type of inhibition, when the end product is at the required level then it gives certain inhibitory signals (called negative feedback) which inhibit the formation of the end product.
6. G-proteins are related to the hormonal action of those hormones requiring a second messenger, C-AMP. They link hormone receptors on the outer surface of the cell and the interior of the cell.
7. Prostaglandins. These are lipid compounds secreted into the tissue fluid by cell membranes of the glandular cells. These control either contraction/relaxation of smooth muscles or dilation/ contraction of blood capillaries. These were first reported in the semen of men and are produced by the prostate gland.
8. Enzyme adenyl cyclase is secreted by the plasma membrane and changes ATP into C-AMP which helps in hormonal action.
9. Sutherland first described the role of C-AMP in hormone action and called it the “Second Messenger”
10. Origin of endocrine glands. Most endocrine glands are endodermal in origin  For example. Thyroid, Parathyroid, Islets of Langerhans, and Gastric glands.
11. Intestinal glands, Thymus, etc. while some are ectodermal in origin For example. Pituitary gland, Hypo-thalamus; Pineal body etc. Gonads are mesodermal in origin while the Adrenal gland is ecto-mesodermal in origin.
12. The sub-neural gland of Herdmania is homologous to the pituitary of vertebrates. Herring bodies. Structures present in the pituitary and store neurosecretory substances of the hypothalamus.
13. The H-shaped endocrine gland is the thyroid.
14. The endostyle of lower chordates like Herdmania, Amphioxus, etc. is homologous to the thyroid gland.
15. When under stress, adrenaline is secreted directly into the blood.
16. Many other organs such as the digestive tract secrete hormones, and erythropoietin from the kidney stimulates RBC production. An atrial natriuretic hormone secreted by the heart helps to regulate salt and water balance and blood pressure.
17. The iodine content of thyroxine is 65% and is called iodized hormone. Thyroxine contains 80% tetra do thyronine (T₄) and 20% triiodo thyroxines (T₃) is more active than T₄
18. Renin. A hormone secreted by the kidney. It helps in erythropoiesis in bone marrow and osmoregulation through the renin-angiotensinogen system. Adiposogenital syndrome of Hypothalamic eunuchoidism. Hypogonadism in males is caused by the genetic inability of the hypothalamus to secrete gonadotrophin-releasing hormones.
19. Contraceptive pills. These contain estrogens and progesterone.
20. Diseases Due To Deficiency/Excess Of Hormones
21. Grave’s disease. (Exophthalmic Goitre)
22. Cause: Hypersecretion of thyroxine due to enlargement of the thyroid gland.
23. Cretinism. Cause: Hyposecretion of thyroxine in children.
24. Myxoedema. Cause. Deficiency of thyroxine in adults

• Symptoms: a. puffy appearance due to accumulation of fats.
• Lack of alertness, and intelligence.
• Slow heartbeat, low BP, decreased body temperature.

1. Iodine Def. Goitre: Deficiency of iodine in diet.

• Symptoms: Enlargement of thyroid gland.

1. Parathyroid tetany : Cause: Deficiency of Parathormone.

• Symptoms: Sustained contraction of muscles of face, pharynx, hands and feet.

1. Addison’s Disease: Cause: Deficiency of mineralocorticoids and glucocorticoids.

• Symptoms: a. low blood sugar, low Na⁺ ion, high K⁺ ion concentration in blood.
• Bronze-like pigmentation of skin.
• Nausea, vomiting, diarrhea.
• Conn’s syndrome (Aldosteronism) Caused due to excessive secretion of aldosterone.

Cushing’s Syndrome. Cause. Excess of cortisol.

• Symptoms, a. High blood sugar, b. Sugar in urine, c. Obesity, d. Wasting of limb muscles
• Adrenal virilism. Excess of sex corticoids in (females) a tendency to develop male characteristics by the female due to imbalances in the secretion of adrenal hormones.
• Dwarfism. Deficiency of GH from early age. It may be Lorrain type, Frohlich type, or Progeria.
• Gigantism. Excess of GH from childhood.
• Acromegaly. Excess of GH after adolescence. The stage is called Acromicria.
• Diabetes Insipidus. Deficiency of ADH.
• Diabetes Mellitus. Deficiency of insulin.
• Eunuchoidism. Failure of testosterone.
• Infantilism. Characteristics of childhood continue beyond the years of puberty. Generally caused due to imbalances in the hormone of the anterior pituitary.
  1. Diabetes is a disease caused by a deficiency of insulin secreted by the pancreas.
  2. Hyperglycemia is an increased blood glucose level than the optimum level.
  3. Hypoglycemia is a lower blood glucose level than the optimum level.
  4. Osteoporosis is a disease caused by hypersecretion of parathormone.

1. Hashimoto’s Disease: Due to a fall in the secretion of thyroxine antibodies start forming against the gland, so the thyroid gets destroyed. It is also known as the suicide of the thyroid.
2. Ridding Henson disorder: It is caused by to deficiency of collip’s hormone as a result of which phosphate level in the blood decreases and Ca_2⁺ level increases.

Acidosis. Excessive loss of Na⁺ is known as acidosis. It may occur due to the hyposecretion of Aldosterone.

Endocrine System Notes For Neet

1. Contributors related to Endocrinology
2. The first hormone was discovered by William M. Bayliss and Earnest H. Starling (1903).
3. The term hormone was introduced by Starling (1905).
4. Selye (1948) defined hormone as a functional chemically complex organic compound.
5. Berthold laid the foundation for the study of the functions of hormones.
6. Scharrer and Scharrer (1936) stated that hormones generally control or regulate reproductive activities, growth, maturation, regeneration, metabolism, and homeostasis. , Huxley called hormones as chemical messengers.
7. Thomas Addison is regarded as the father of endocrinology.
8. Claude Bernard (1955) established that the nervous system controls the function of endocrine glands.
9. The action of insulin hormone was demonstrated by Banting and later by Best. Shaefer (1912) gave the name insulin.
10. F. Sanger (1954) worked out the molecular structure of insulin. He established that it is polypeptide and was awarded the Nobel Prize (1958). i
11. Human insulin was synthesized by Tsan in 1965.
12. Kimball and Murlin discovered glucagon.
13. Karlson and Burtenandt coined the term pheromones.
14. Kochar (1916) isolated thyroxine (pure form).
15. Kendall (1919) obtained a crystallized form of thyroxine.
16. Harrington and Barges (1927) worked out the molecular structures of thyroxine.
17. Gudernatch (1912) discovered that metamorphosis in a frog’s tadpole begins only when an adequate amount of thyroxine is secreted by the thyroid of the tadpole.
18. Aldrich (1901) worked out the molecular structures of adrenaline and noradrenaline.
19. Stolz (1904) and Dakin (1905) synthesized adrenaline.
20. Enterocrinin. This hormone was isolated by Nasset from both small and large intestinal mucosa

Hormones And Endocrine Glands Neet Notes

• The nervous system and endocrine system together regulate the working of the body.
• Hormones affect all the cells of a target organ whereas a neuron will affect only a single muscle or fraction of it.
• A hormone is a chemical messenger secreted by the endocrine gland and carried to the target organ by blood.
• The pituitary gland is pea-shaped, 1.3 cm in diameter, and weighs only 0.5 gm.
• The pituitary is attached to the hypothalamus of the brain by a stalk-like structure called the infundibulum.
• Region of pituitary
• Anterior lobe (Adenohypophysis)
• Posterior lobe (Neurohypophysis)
• A third region is termed the intermediate lobe or pars intermedia.
• Neurons of the autonomic system stimulate hormone release from some glands. For instance, adrenaline and noradrenaline are released from the adrenal medulla on the arrival of nerve impulses during anxiety, stress, and danger. Thus endocrine system is considered a chemical extension of the nervous system.
• Corticotropes. about 20 % and secrete ACTH.
• Gonadotropes. secrete FSH and LH in female ; and FSH and ICSF1 in male.
• The gastrointestinal lining also secretes several hormones that regulate the secretion of digestive juices.
• Thymosin secreted by the thymus stimulates the maturation of immune system cells. Melatonin controls skin shade in some animals and appears to control annual reproductive cycles. Some hormones, such as steroid hormones, act by binding to DNA and altering gene expression.
• Other hormones bind to membrane receptors, where they either open ion channels (usually Ca₂⁺) or trigger the production of other chemical messengers inside the cell. Typically the receptor activates an enzyme via a G protein intermediate, which generates c AMP, which in turn activates the first step in an enzyme cascade.
• Cellular reactions are faster and more accurate when activity is determined by the ratio of two antagonistic hormones rather than the absolute level of a single hormone.

NEET Biology Endocrine System Quanta To Memory

1. Hormonology. Study of hormones.
2. Hormonotherapy. Treatment by hormones.
3. Largest Endocrine Gland. The thyroid (25 to 40 gms) is the largest endocrine gland in the human body.
4. Trophins (Tropins). The hormones which stimulate an endocrine gland to secrete its hormone (s,), For example.,  thyrotrophic hormone that stimulates the thyroid gland to secrete thyroxine.
5. All the pituitary hormones are molecules made chiefly of monomers of amino acids
6. The anterior pituitary has been called the master gland, because of the tropic hormones it releases. The real master “gland,” however, is the hypothalamus because its hormones regulate the secretory activity of the anterior pituitary.
7. Anterior and intermediate lobes of pituitary form adenohypophysis derived from Rathke’s pouch are ectodermal in origin.
8. The posterior lobe or neurohypophysis arises from the floor of the hypothalamus.
9. Rathke’s pouch: an embryonic outgrowth of the pharynx which forms adenohypophysis of the pituitary gland. Median eminence is a part of the posterior pituitary
10. Adenohypophysis gets its blood supply through the circle of Willis
11. In comparison with the nervous system, hormones are distributed by blood but slowly.
12. Hormonal action is generally less specific in comparison with nervous regulation.
13. Kyphosis. Hunched back in the person suffering from acromegaly.
14. Lag period. The period between secretion of hormone from the endocrine gland and biological response from the target organ.
15. Baldness. It is related to the sex hormones. Male sex hormone promotes baldness, female sex hormones inhibit it.
16. Melatonin is a hormone secreted by the pineal body and controls skin pigmentation.
17. Sella turcica is the pituitary fossa (a depression in the skull in which the pituitary gland lies).
18. Somatotropes are cells of the pituitary gland that secrete growth hormone (also called STH).
19. Thymosin is a hormone secreted by the thymus gland and increases the activity of T-lymphocytes.
20. Islets of Langerhans. These are approximately 1 to 2 million small clusters of endocrine cells which are named after the name of their discoverer (1869). Prostaglandins and leukotrienes are important eicosanoids.
21. These are local hormones and are derived from a 20-carbon fatty acid called arachidonic acid. Contraceptive pills contain the hormones estrogen and progesterone.
22. Melanocyte-stimulating hormone is secreted by the middle lobe of the pituitary. It darkens the skin of many animals including fishes and amphibians. It results from the stimulation of the synthesis of melanin in the skin.
23. Gravidex test is for detecting the presence of HCG hormone in the urine in case of pregnancy
24. Parathormone is a protein hormone consisting of 84 amino acids.
25. The British biologist V.B. Wigglesworth discovered, in the 1930s, two hormones that regulate development in insects. One is ecdysone, which promotes growth, molting, and the development of adult traits.
26. It is produced by the prothoracic glands in the head or thorax. The other hormone is juvenile hormone which promotes retention of larval characteristics. It is produced by the corpora allata glands in the head.
27. Of the two insect hormones discovered by Wiggles Worth, ecdysone has no role in the adult insect, whereas juvenile hormone promotes the development of eggs and sperm.
28. Prolactin and oxytocin are being used for increasing milk yield among dairy cattle. Recently genetically engineered Bovine growth hormone (BGH) was also used to boost milk yield in cows but was banned in March 1995.
29. The melanocyte-stimulating hormone was previously known as intermedin.
30. The adrenal gland is also known as the 3F gland (Fear, Flight, Fright)
31. Oral insulin is given as IZS [Insulin zinc suspension] or PZS (Protamine zinc suspension)
32. Hassels’ corpuscles are found in the thymus and are known as Thymic cells.
33. a-and (3-chains of insulin are connected through disulfide bonds.
34. The thymus is associated with our immune system. It acts as a lymphatic gland.
35. Humulin is a human insulin, produced by DNA recombinant technology.
36. Allaxonic diabetes is due to allaxon which destroys beta cells of the pancreas.
37. The adrenal gland is also known as the 3-F gland and the 4-S gland.
38. Oral contraceptive pills with a synthetic form of estrogen and progesterone hormones prevent ovulation in the female. Milk secreting hormone is prolactin and milk ejecting hormone is oxytocin.
39. The pregnancy hormone is progesterone and the birth hormone is oxytocin.

NEET Biology Endocrine System Multiple-Choice Questions

Question 1. Hormones Chemically Are :

1. Proteins
2. Fatty Acid Derivatives
3. Steroids
4. All The Above.

Answer: 4. All The Above

Question 2. Hormonal Diseases May Be Called :

1. Functional Diseases
2. Deficiency Diseases
3. Infectious Diseases
4. All The Above.

Answer: 1. Functional Diseases

Question 3. Which Of The Following Is A Hormonal Disease?

1. Measles
2. Rabies
3. Tuberculosis
4. Osteitis Fibrosa Cystica.

Answer: 4. Osteitis Fibrosa Cystica.

Question 4. A Hormone Is A Molecule That:

1. Moves Through The Blood Stream And Ducts
2. Influences Development
3. Has The Same Chemical Activity In A Variety Of Organisms
4. Alters The Activity Of Certain Non-Adjacent Cells.

Answer: 4. Alters The Activity Of Certain Non-Adjacent Cells

Neet Previous Year Questions On Endocrine System

Question 5. Adrenaline Is Secreted By :

1. Pituitary Gland
2. Pineal Gland
3. Adrenal Gland
4. Thymus Gland.

Answer: 3. Adrenal Gland

Question 6. Corticoids Are Secreted By :

1. Thymus
2. Adrenals
3. Pancreas
4. Kidney.

Answer: 2. Adrenals

Question 7. Islets Of Langerhans Secrete :

1. Adrenaline
2. Acth
3. Fsh
4. Insulin.

Answer: 4. Insulin.

Question 8. Based on the Chemical Nature Of Hormones, They Are Divided Into :

1. Two Categories
2. Three Categories
3. Five Categories
4. Six Categories.

Answer: 4. Six Categories.

Question 9. α-Cells Of Adenohypophysis Secrete Which Hormone?

1. ACTH And LH
2. GH And LTH
3. FSH And LH
4. TSH And FSH.

Answer: 2. GH And LTH

Question 10. The Trophic Factors Are Made Up Of Proteins Containing :

1. 1 To 4 Amino Acids
2. 4 To 10 Amino Acids
3. 3 To 15 Amino Acids
4. 3 To 20 Amino Acids.

Answer: 4. 3 To 20 Amino Acids.

Question 11. Which One Of The Following Is Not Synthesized In the Pituitary?

1. Lactotrophic
2. TSH
3. ICSH
4. ADH

Answer: 1. Lactotrophic

Question 12. Acth Is Secreted By :

1. Pineal Body
2. Anterior Lobe Of Pituitary Gland
3. Posterior Lobe Of Pituitary Gland
4. Thymus.

Answer: 2. Anterior Lobe Of Pituitary Gland

Question 13. Adh Is Produced By :

1. Pineal Body
2. Anterior Lobe Of Pituitary Body
3. Thymus
4. Posterior Lobe Of Pituitary Body.

Answer: 4. Posterior Lobe Of Pituitary Body.

Question 14. Which Of The Following Substances Is Released In Excess Quantity During Excitement?

1. Cortisone
2. Serotonin
3. Adrenaline
4. Nor-Epinephrine.

Answer: 3. Adrenaline

Adrenal Gland Hormones NEET Biology

Question 15. Which Of The Following Structures Act As Temporary Ductless Gland?

1. Pancreas
2. Pineal
3. Parathyroid
4. Placenta.

Answer: 4. Placenta

Question 16. Which Of The Following Secretory Glands Acts Both As Endocrine And Exocrine?

1. Adrenal
2. Parathyroid
3. Pancreas
4. Pineal.

Answer: 3. Pancreas

Question 17. Like Muscles, Hormones Are Antagonistic In Their Functioning. Mark The Wrong One :

1. Calcitonin And Parathormone
2. Insulin And Glucagon
3. Tsh And Thyroxine
4. Somatostatin And Growth Hormone.

Answer: 3. Tsh And Thyroxine

Question 18. The Hormone Released From the Intermediate Lobe Of the Pituitary Is:

1. FSH
2. LH
3. MSH
4. ACTH.

Answer: 3. ACTH

Question 19. Secretion Of The Following Hormones Results In Cretinism :

1. Thyroxine
2. Testosterone
3. Calcitonin
4. ADH.

Answer: 1. Thyroxine

Question 20. Vasopressin Is Related With :

1. Concentration Of Urine
2. Dilution Of Urine
3. Quick Digestion
4. Slow Heart Beat.

Answer: 1. Concentration Of Urine

Question 21. Which Of The Following Statements Is False?

1. Hormones Produced In Ovary Affects The Uterine Cycle
2. Hormones Produced In Small Intestine Stimulate Heart
3. Hormones Produced In Adrenal Medulla Stimulate HeartBeat
4. Hormones Produced In Thyroid Stimulate Metabolism.

Answer: 2. Hormones Produced In the Small Intestine Stimulate the Heart

Hormonal Disorders And Imbalances Neet Notes

Question 22. The Target Cells Of A Hormone Always Have :

1. Special Receptors To Which The Hormones Bind
2. Special Channels Through Which The Hormones Move
3. Large Amounts Of Hormones Stored Within Vesicles.
4. Undifferentiated Cytoplasm.

Answer: 1. Special Receptors To Which The Hormones Bind

Question 23. The Cells That Produce Glucagon In Pancreas Are :

1. α Cells
2. β Cell
3. ϒ Cells
4. Acinar Cells.

Answer: 1. α Cells

Question 24. Calcium Ions Are Important In The Body Because They :

1. Are Involved As Co-Factors
2. Regulate Many Intercellular Metabolism
3. Influence Membrane Permeability
4. All The Above.

Answer: 4. All The Above.

Question 25. Fsh Is Produced By :

1. Posterior Lobe Of Pituitary Body
2. Middle Lobe Of Pituitary Body
3. Anterior Lobe Of Pituitary Body
4. Adrenal Cortex.

Answer: 3. Anterior Lobe Of Pituitary Body

Question 26. A Short Individual, Fairly Well Proportioned Body, Who Is Mentally And Physically Normal, Developed Due To The Undersecretion Of Growth Hormones, This Stage Is :

1. Lorrain’S Type
2. Frohlich’S Type
3. Acromegaly
4. Acromicria.

Answer: 1. Lorrain’s Type

Question 27. Adrenal Medullary Hormones Are Produced When :

1. Neurohypophysis Is Stimulated
2. Adenohypophysis Is Stimulated To Produce Oxytocin
3. Under Stress
4. Breeding Phase Starts.

Answer: 3. Under Stress

Question 28. Estrogen Is Necessary For :

1. Development And Maintenance Of Uterus
2. Proper Functioning Of Fallopian Tube
3. Normal Functioning Of The Cervix And Vagina
4. Development Of Secondary Sexual Characters In Females.

Answer: 4. Development Of Secondary Sexual Characters In Females.

Question 29. Vasopressin And Oxytocin Are Secreted By :

1. Hypothalamic Neurosecretory Cells
2. Neurohypophysis
3. Medulla
4. Pancreas.

Answer: 1. Hypothalamic Neurosecretory Cells

Question 30. Adrenal Cortical Cells Are Stimulated By :

1. Corticotropins From The Hypothalamus
2. Adreno Corticotropic Hormones
3. Corticoids
4. Changes In Blood Glucose Level.

Answer: 2. Adreno Corticotropic Hormones

Question 31. Many Hormones Are Initially Synthesised As Biologically Inactive Precursor Molecules Called :

1. Ectohormones
2. Pheromones
3. Endorphins
4. Prohormones.

Answer: 4. Prohormones.

Question 32. Rate Of Hormones Synthesis And Secretion Depend Upon :

1. Functional Efficiency Of The Feedback
2. Amount Of Excitation In Target Tissue
3. Degree Of Inhibition Causes
4. Functional State Of Tissue.

Answer: 1. Functional Efficiency Of The Feedback

Endocrine System Notes For Neet

Question 33. Thyrotrophic Releasing Hormone Is :

1. A Neurosecretion From The Hypothalamus Which Stimulates Anterior Lobe Of Pituitary
2. A Secretion Of Pars Distalis
3. Elaboration Of Neurohypophysis
4. From Thyroid Gland.

Answer: 1. A Neurosecretion From The Hypothalamus that stimulates the Anterior Lobe Of the Pituitary

Question 34. Involvement Of Any Hormone In The Control Of Cellular Function Depends On A Series Of Reactions Involving :

1. Synthesis Of Hormone In The Endocrine Cells
2. Feedback Control
3. Beginning With Hormone Synthesis And Finishing With Feedback Control
4. None Of The Above.

Answer: 3. Beginning With Hormone Synthesis And Finishing With Feedback Control

Question 35. Hormones Regulating The Morphogenetic Effects Are :

1. Growth Hormone
2. Testosterone
3. Androgens
4. All Of The Above.

Answer: 4. All Of Above.

Question 36. If the Ovaries Of A Lady Are Removed In The Fourth Month Of Pregnancy, The Result Will Be :

1. Embryo Will Develop Normally Till Birth
2. Abortion Will Occur After Some Time
3. Development Of Embryo Become Improper
4. None Of The Above.

Answer: 1. Embryo Will Develop Normally Till Birth

Question 37. A Substance Called ADH Is:

1. A Hormone That Promotes Glycogenesis In Liver Cell
2. An Enzyme Secreted By Cells Of Intestinal Wall; Hydrolyses Dipeptides Into Amino Acids
3. A High Energy Compound Involved In Muscle Contraction
4. A Pituitary Secretion Which Promotes Reabsorption Of Water From Glomerular Filtrate.

Answer: 4. A Pituitary Secretion that promotes Reabsorption Of Water From Glomerular Filtrate.

Question 38. The Pancreas Is A Mixed Gland In Which :

1. All Cells Secrete Enzymes And Hormones
2. Most Cells Secrete Hormones
3. A Few Cells Secrete Enzymes
4. Enzymes And Hormones Are Secreted By Separate Cells.

Answer: 4. Enzymes And Hormones Are Secreted By Separate Cells.

Question 39. Treatment With Alloxan Destroys :

1. STH Cells
2. β- cells of Islets Of Langerhans
3. Cells Of Sertoli
4. Cells Of Leydig.

Answer: 2. Islets Of Langerhans

Question 40. Select The Correct Answers To The Followings. Which Of The Following Techniques Should Be Least Likely To Help Elucidate The Function Of A Hormone Produced By An Endocrine Gland?

1. Removal Of The Gland And Subsequent Analysis Of What Functions Are Lost
2. Transplantation Of The Gland Into An Animal That Lacks The Gland
3. Transfusion Of Blood From An Animal Lacking The Gland Into An Animal That Has The Gland And Observation Of Its Effects
4. Observing Effects Of Gland Extract On Various Tissues Grown In Culture.

Answer: 3. Transfusion Of Blood From An Animal Lacking The Gland Into An Animal That Has The Gland And Observation Of Its Effects

Question 41. All The Following Commonly Serve As Signals Stimulating Hormone Secretion Except:

1. Conditions Outside The Body
2. Rising Levels Of Another Hormone
3. Rising Levels Of The Hormone In Question
4. Falling Levels Of The Hormone In Question.

Answer: 3. Rising Levels Of The Hormone In Question

Endocrine System Notes For Neet

Question 42. Hormones Are Known To Cause All The Following Changes In Target Cells Except:

1. Changes In Genetic Make-Up
2. Change In Permeability
3. Change In Metabolic Rate
4. Increase In Cyclic Amp Concentration.

Answer: 1. Changes In Genetic Make-Up

Question 43. An Advantage Of Having The Endocrine System As Well As The Nervous System Involved In The “Fight Or Flight” Response:

1. The Endocrine System Responds Faster
2. The Endocrine Response Usually Lasts Longer
3. The Endocrine System Is Turned More Precisely To The Degree Of Need
4. The Endocrine System Affects Only The Target Organ Whose Response Is Needed To Meet The Emergency.

Answer: 4. The Endocrine System Affects Only The Target Organ Whose Response Is Needed To Meet The Emergency.

Question 44. In Case Of Hypersecretion Of A Parathormone, Some Cells Of the Body Become Overactive. These Cells Are :

1. Ependymal Cells
2. Sarcoplasmic Reticulum
3. Osteoclasts
4. Osteocytes.

Answer: 3. Osteoclasts

Question 45. Hormones Controlling Expression Of Secondary Sexual Characters Are Secreted By Which Of These Cells In The Testis?

1. Sertoli Cells
2. Spermatogonia
3. Leydig’S Cells
4. Primary Spermatocytes.

Answer: 3. Leydig’s Cells

Question 46. Hormones Which Helps In The Implantation Of Embryo In Uterus Is :

1. Estrogen
2. Thyroxine
3. Relaxin
4. Progesterone.

Answer: 4. Progesterone

Question 47. In The Areas Of Destruction In The Bones, Fibrous Cysts Develop However The Parathyroid Becomes Overactive. This Is The :

1. Osteitis Fibrosa Cystica
2. Polydipsia
3. Osteomalacia
4. None.

Answer: 1. Osteitis Fibrosa Cystica

Question 48. Anti-Allergic Hormone Is :

1. Epinephrine
2. Non-Epinephrine
3. Gluco-Corticoid
4. Mineralo-Corticoid.

Answer: 3. Gluco-Corticoid

Question 49. Cretinism Is Due To :

1. Hypothyroidism In Children
2. Hypothyroidism In Adults
3. Hyperthyroidism In Children
4. Hyperthyroidism In Adults.

Answer: 1. Hypothyroidism In Children

Hormones And Endocrine Glands Neet Notes

Question 50. Which Of The Following Is Not Necessarily Property Of All Hormones?

1. Carrying Information
2. Secreted In Small Amounts
3. Short Half-Life
4. Proteinic Nature.

Answer: 4. Proteinic Nature.

Question 51. One Of The Following Hormones Is Not Produced By Alimentary Canal. Select?

1. Insulin
2. Cholecystokinin
3. Secretin
4. Gastrin.

Answer: 1. Insulin

Question 52. The True Proteinaceous Hormones Are Secreted By :

1. Pancreas
2. Anterior Lobe Of Pituitary
3. Posterior Lobe Of Pituitary
4. Thyroid.

Answer: 2. Anterior Lobe Of Pituitary

Question 53. What Does The Growth Hormone Do When the Growth Period Is Over:

1. Regulates Metabolism
2. Promotes Reproductive Activities
3. Stimulates Growth Of Secondary Sexual Characters
4. Stimulates Gametogenesis.

Answer: 1. Regulates Metabolism

Question 54. Strong Emotional Attachment To The Young Ones Is Due To:

1. Emotional Hormones Like Epinephrine And Gluco-Corticoids
2. Luteotropic Hormone (Lth)
3. Lh
4. All.

Answer: 2. Luteotropic Hormone (Lth)

Question 65. Secretion Of Vasopressin Is :

1. Acyclic And Not Affected By Seasonal Changes
2. Cyclic Phenomenon With Seasonal Changes
3. Effect Of Exercise
4. A Regular And Constant Feature.

Answer: 1. Acyclic And Not Affected By Seasonal Changes

Question 66. Precursor Chemical For Steroid Hormones Are:

1. Cholesterol
2. Nucleic Acid
3. Amino Acid
4. Mucoprotein.

Answer: 1. Cholesterol

Question 67. Function Of Progesterone Is :

1. Preparation Of Uterus For Pregnancy
2. To Maintain The Pregnancy
3. To Complete The Formation Of Milk In The Mammary Glands
4. Both  1 And 2.

Answer: 2. To Maintain The Pregnancy

Endocrine System NEET Notes

Question 68. A New Menstrual Cycle Starts When :

1. Pituitary Resumes Lh Production In The Absence Of Fsh And Progesterone
2. Ovary Resumes Progesterone Production In the Presence Of Lh
3. Ovary Resumes Estrogen Production In The Presence Of Fsh
4. Pituitary Resumes Lh Production In The Presence Of Fsh And Progesterone.

Answer: 3. Ovary Resumes Estrogen Production In The Presence Of Fsh

Question 69. Diabetes Mellitus Is Caused By Deficiency Of:

1. Secretin
2. Adrenaline
3. Insulin
4. Prolactin.

Answer: 3. Insulin

Question 70. The Growth Of Facial And Body Hair In Male Is Stimulated By :

1. Pituitary Hormones
2. Thyroxine
3. Parathyroid
4. Androgenic Hormones.

Answer: 4. Androgenic Hormones.

Question 71. The Phenomenon Of ‘Heat’ Or Oestrus In Females Is Due To The Hormones Secreted By :

1. Pituitary
2. Thyroid
3. Interstitial Cells Of Testes
4. Ovarian Follicles.

Answer: 4. Ovarian Follicles.

Question 72. Hyperadrenalism Is Called :

1. Cushing’S Disease
2. Addison’S Disease
3. Simmond’S Disease
4. None.

Answer: 1. Cushing’s Disease

Question 73. Which Of The Pituitary Hormones Is Responsible For The Secretion Of Milk By The Mammary Glands In Females?

1. ACTH-RH
2. LH And Prolactin
3. LTH-RH
4. TH.

Answer: 2. LH And Prolactin

Question 74. Which One Of The Endocrine Glands Shrinks After The Start Of Adolescence?

1. Pituitary Body
2. Pineal Glands
3. Hypothalamus
4. Thymus Glands.

Answer: 4. Thymus Glands.

Question 75. The Hormone That Regulates The Growth Of The Skeleton And The Body As A Whole Is :

1. Thyroxine
2. Parathormone
3. Thyroid Stimulating Hormone
4. Human Growth Hormone.

Answer: 4. Human Growth Hormone.

Question 76. Which One Of The Following Has an Anti-Insulin Effect?

1. Calcitonin
2. Cortisol
3. Oxytocin
4. Aldosterone.

Answer: 2. Cortisol

Question 77. Which Of The Following Hormones Is Proteinic In Nature But May Be Secreted By An Organ Which Normally Secretes Steroids Under Special Conditions Is :

1. Relaxin
2. LH
3. Estrogen
4. Oxytocin.

Answer: 1. Relaxin

Question 78. The Addison’s Disease Is Caused By The :

1. Hyposecretion Of Cortical Hormones
2. Hypersecretion Of Cortical Hormones
3. Hypersecretion Of Pituitary Hormones
4. Enlargement Of Thyroids.

Answer: 1. Hyposecretion Of Cortical Hormones

Question 79. The Determination And Masculinisation Of Female May Be Done By :

1. Ovary
2. Medulla Of Adrenals
3. Cortex Of Adrenals
4. Parathyroids.

Answer: 3. Cortex Of Adrenals

Question 80. Select The Odd One :

1. Insulin
2. Oxytocin
3. Thyroxine
4. Ecdysone.

Answer: 4. Ecdysone.

Question 81. Progesterone Is A / An :

1. Enzyme
2. Protein
3. Hormone That Relaxes Uterus During Birth
4. Hormone Responsible For Growth And Maintenance Of Foetus.

Answer: 4. Hormone Responsible For Growth And Maintenance Of Foetus.

Question 82. Which Hormone Of The Following Endocrine Glands Lacks Peptide, Amines And Sulphur?

1. Hormones Of the Anterior Lobe Of the Pituitary
2. Hormones Of the Posterior Lobe Of the Pituitary
3. Hormones Of Thyroids And Adrenal Gland
4. Hormones Of Gonads.

Answer: 4. Hormones Of Gonads.

Hormones And Endocrine Glands Neet Notes

Question 83. Which Endocrine Gland Stores Its Secretion In The Extracellular Space Before Discharging It Into The Blood?

1. Adrenal
2. Pancreas
3. Testis
4. Thyroid.

Answer: 4. Thyroid.

Question 84. According To The Accepted Concept Of Hormone Action, If Receptor Molecules Are Removed From Target Organs :

1. The Target Organ Will Continue To Respond To The Hormone Without Any Difference
2. The Target Organ Will Continue To Respond To The Hormone But Will Require Higher Concentration
3. The Target Organ Will Not Respond To The Hormone
4. The Target Organ Will Continue To Respond To The Hormone But In The Opposite Way.

Answer: 3. The Target Organ Will Not Respond To The Hormone

Question 85. Oxytocin Is A :

1. Parathormone
2. Small Peptide
3. Fatty Acid Residue
4. Sugar Molecule.

Answer: 2. Small Peptide

Question 86. The Hormone that elevates Blood Calcium And Phosphorus levels is:

1. Parathormone
2. Calcitonin
3. Thyroxine
4. Triiodothyronine.

Answer: 1. Parathormone

Question 87. The Hormone Which Stimulates Milk Production In Mammals Is Known As:

1. Glucagon
2. Prolactin
3. Progesterone
4. Oestrogen.

Answer: 2. Prolactin

Question 88. Which Of The Following Is Not a Steroid?

1. Testosterone
2. Oestradiol-17b
3. Progesterone
4. Prolactin.

Answer: 4. Prolactin.

Question 89. Which Of The Following Hormones Stimulate the Conversion Of Proteins Into Amino Acids Particular During Fasting Or Hibernation?

1. Glucocorticoids
2. Secretin
3. Adrenaline
4. Enterogastrone.

Answer: 1. Glucocorticoids

Question 90. Growth Hormone Is Secreted By :

1. Hypothalamus
2. Thyroid Glands
3. Pituitary Gland
4. Pineal Body.

Answer: 3. Pituitary Gland

Question 91. The Hormone In the Pineal Gland Is Called :

1. Melatonin
2. Melatonin
3. Serotonin
4. Pincolin.

Answer: 1. Melatonin

Question 92. The Pineal Gland :

1. Is A Photoreceptor
2. Responds To Smell
3. Responds To Sound
4. Is Sensitive To Light Stimulus.

Answer: 4. Is Sensitive To Light Stimulus.

Neet Biology Endocrine System Notes Pdf

Question 93. Endocrinology Term Was Proposed By :

1. Pande
2. Hardy
3. Sutherland
4. All Of These.

Answer: 1. Pande

Question 94. Hormones Are Needed In :

1. Gms.
2. Milligrams
3. Nanograms
4. Kilograms.

Answer: 3. Nanograms

Question 95. Pheromones Are :

1. Hormones Of Insects
2. Peripheral Hormones
3. Both 1 And 2
4. None.

Answer: 3. Both 1 And 2

Question 96. The Total No. Of Hormones Produced By Adrenal Cortex Is 20 But They Are Grouped Under :

1. One
2. Two
3. Three
4. Four.

Answer: 3. Three

Question 97. Calcitonin, Which Reduces The Excessive Amount Of Calcium Of The Blood, Is Secreted By The :

1. Hypothalamus
2. Parathyroid
3. Thyroid
4. Adrenal.

Answer: 3. Thyroid

Question 98. The Vesicles Of The Thyroid Gland Are Lined By :

1. Epithelium Which Is Single Layered
2. A Double Layer Of Epithelium
3. A Single Layer Of Endothelium
4. A Double Layer Of Endothelium.

Answer: 1. Epithelium Which Is Single Layered

Question 99. The Moulting In Insects Is Triggered Off By :

1. Thyroxine
2. Ecdysone
3. Juvenile Hormone
4. Pheromone.

Answer: 2. Ecdysone

Question 100. The Hormones Secreted By Hypothalamus Are Carried To The Pituitary Gland By :

1. Hypophyseal Stalk
2. Hypophyseal Portal System
3. Neural Complex
4. Neuro-Hypophyseal Portal System.

Answer: 2. Hypophyseal Portal System

Question 101. Cretinism In Children Is Caused By :

1. Hypothyroidism
2. Hypopituitarism
3. Hypoparathyroidism
4. Hypo-Insulin-Secretion.

Answer: 1. Hypothyroidism

Hormones And Endocrine Glands Neet Notes

Question 102. Mammalian Thymus Is Mainly Concerned With :

1. Regulation Of Body Growth
2. Regulation Of Body Temperature
3. Immunological Functions
4. Secretion Of Thyrotropins.

Answer: 3. Immunological Functions

Question 103. Insulin Was Extracted First By :

1. Flemming
2. Khorana
3. Watson And Crick
4. Banting And Best.

Answer: 4. Banting And Best.

Question 104. The Effect Of Different Hormones On The Body Can Be Best Said To Bring About:

1. Stimulation Of Organs
2. Release Of Inherent Capacities
3. Proper Growth
4. Coordination Of Functions.

Answer: 4. Coordination Of Functions.

Question 105. Which Hormone Has The Anti-Insulin Effect?

1. Calcitonin
2. Cortisol
3. Oxytocin
4. Glucagon.

Answer: 2. Cortisol

Question 106. Hypoparathyroidism Results Due To :

1. Upset In Metabolism
2. Improper Gonadial Function
3. Convulsions And Tetany
4. Nervousness And Wasting.

Answer: 3. Convulsions And Tetany

Question 107. The Secretion From Which Of The Following Controls Wall Balance In The Body?

1. Cerebellum
2. Cerebrum
3. Pineal Body
4. Pituitary.

Answer: 4. Pituitary.

Question 108. Hypothyroidism In Adult Causes :

1. Cretinism
2. Exophthalmic Goitre
3. Myxoedema
4. Graves’s Disease

Answer: 3. Myxoedema

Question 109. Insulin Promotes :

1. Glycogenesis
2. Glycolysis
3. Glyconeogenesis
4. Glycogenolysis.

Answer: 1. Glycogenesis

Question 110. Mark The Gland In Whose Presence Sex Glands Fail To Develop :

1. Adrenal
2. Pituitary
3. Pineal
4. Thyroid.

Answer: 3. Pineal

Question 111. The Anterior Lobe Of Pituitary Affects :

1. Protein Metabolism
2. Fat Metabolism
3. Carbohydrate Metabolism
4. All Of The Above.

Answer: 4. All Of The Above.

Question 112. Survival Time Can Be Minimized If We Remove:

1. Adrenal
2. Pituitary
3. Thymus
4. Thyroid.

Answer: 1. Adrenal

Question 113. Testis Secretes Androgen, It Is :

1. Testosterone
2. Androsterone
3. Progesterone
4. Aldosterone.

Answer: 1. Testosterone

Question 114. Which Of The Following Causes Ageing?

1. Islets Of Langerhans
2. Parathyroid
3. Thyroid
4. Thymus.

Answer: 4. Thymus.

Hormones And Endocrine Glands Neet Notes

Question 115. Breast Development During Pregnancy Is Induced By :

1. Estradiol
2. Progesterone
3. Relaxin
4. None Of These.

Answer: 2. Progesterone

Question 116. Which Of The Following Is Helpful For An Asthma Patient In Exhaling The Air?

1. Adrenaline
2. Insulin
3. Oxytocin
4. Thyroxine.

Answer: 1. Adrenaline

Question 117. Which Of The Following Controls Thirst?

1. Adrenal
2. Pituitary
3. Parathyroid
4. Thyroid.

Answer: 2. Pituitary

Question 118. Complete Failure Of Adenohypophysis Of Pituitary In Adult Women Causes :

1. Addison’S Disease
2. Cushing’S Disease
3. Dwarfism
4. Simmond’s Disease.

Answer: 3. Dwarfism

Question 119. Oxytocin Is Secreted By :

1. Adenohypophysis
2. Neurohypophysis
3. Hypophyseal Stalk
4. Only Pregnant Women.

Answer: 2. Neurohypophysis

Question 120. Fsh Is Produced By :

1. Adrenal
2. Thyroid
3. Anterior Lobe Of Pituitary
4. Posterior Lobe Of Pituitary.

Answer: 3. Anterior Lobe Of Pituitary

Question 121. Which Of The Following Hormones Is From the Parathyroid Gland?

1. Epinephrine
2. Gastrin
3. Noradrenaline
4. Parathormone.

Answer: 4. Parathormone.

Question 122. Thyroxine Is Produced Through :

1. Chlorination Of Serine
2. Iodination Of Isoleucine
3. Iodination Of Tyrosine
4. Phosphorylation Of Amino Acids.

Answer: 3. Iodination Of Tyrosine

Question 123. Which Of The Following Is Related To The Production Of Lymphocytes And Antibodies?

1. Thymus
2. Hypothalamus
3. Thyroid
4. Leydig Cells.

Answer: 1. Thymus

Question 124. Addison’s Disease Is Due To the Malfunctioning Of the:

1. Adrenal Cortex
2. Parathyroid
3. Pineal Gland
4. Pancreas.

Answer: 1. Adrenal Cortex

Question 125. The Recently Reported Hormone, Angiotensin Is Secreted By :

1. Liver
2. Kidney
3. Pancreas
4. Placenta.

Answer: 1. Liver

Question 126. Thyroxine Plays Significant Effect On :

1. Carbohydrate Metabolism
2. Protein Metabolism
3. Vitamin Metabolism And Central Nervous System
4. All Of The Above.

Answer: 3. Vitamin Metabolism And Central Nervous System

Question 127. Continued Secretion Of Milk Is Maintained By :

1. Prolactin
2. Progesterone
3. Oestrogen
4. Relaxin.

Answer: 1. Prolactin

Question 128. The Over-Secretion Of Which Of The Following Pituitary Hormones Causes Acromegaly (Irregularly Development Of Bones)?

1. ACTH
2. LH
3. GTH
4. STH Or GH.

Answer: 4. STH Or GH.

Question 129. Hormone Responsible For The Implantation Of Embryo In Uterus And Formation Of Placenta Is :

1. Adrenaline
2. Progesterone
3. Estradiol
4. FSH.

Answer: 2. Progesterone

Question 130. The Pituitary Gland’s Posterior Lobe Produces Two Hormones Called :

1. Cortisone And Corticosterone
2. Progesterone And Estradiol
3. Testosterone And Androsterone
4. Vasopressin And Oxytocin.

Answer: 4. Vasopressin And Oxytocin.

Question 131. According To Recent Knowledge, The Pineal Body Is Considered As :

1. An Organ Of Intelligence
2. An Endocrine Gland
3. A Vestigial Organ
4. An Organ Of Involuntary Action.

Answer: 2. An Endocrine Gland

Neet Previous Year Questions On Endocrine System

Question 132. Which Hormone Is Responsible For The Relaxation Of The Ligaments Of The Pelvic Girdles In Females At The Time Of Birth?

1. Corpus Luteum
2. Gastrin
3. Estradiol
4. Relaxin.

Answer: 4. Relaxin.

Question 133. Who Studied The Effect Of Thyroxine On Metamorphosis :

1. Huxley
2. Starling
3. Kendall
4. Gudernatsch.

Answer: 4. Gudernatsch.

Question 134. Correct Hormonal Sequence In The Increase Of Menstruation Is:

1. Estrogen, Fsh And Progesterone
2. Estrogen, Progesterone And Fsh
3. Fsh, Progesterone And Estrogen
4. Fsh, Estrogen And Progesterone.

Answer: 4. Fsh, Estrogen And Progesterone.

Question 135. Hormone Secreted By Posterior Lobe Of Pituitary Is Concerned With :

1. Metabolism Of Carbohydrates
2. Stimulation Of Thyroid
3. Secondary Sexual Characters
4. Contraction Of Uterus.

Answer: 4. Contraction Of Uterus.

Question 136. Hormone-secreting cells, Called Neurosecretory Cells, Are Abundant In The following:

1. Hypothalamus
2. Amygdala
3. Cerebral Cortex
4. Medulla Oblongata.

Answer: 1. Hypothalamus

Question 137. Oxytocin And Antidiuretic Hormone Reach The Posterior Pituitary By Way Of :

1. The Anterior Pituitary Gland
2. Lymphatic Vessels
3. Blood Vessels
4. Axons.

Answer: 4. Axons.

Question 138. Oxytocin And Antidiuretic Hormone Reach Their Target Cells By Way Of :

1. The Anterior Pituitary Gland
2. Lymphatic Vessels
3. Blood Vessels
4. Axons

Answer: 3. Blood Vessels

Question 139. The Luteinising Hormone Is Secreted By :

1. Lactotrophs
2. Gonadotrophs
3. Thyrotrophs
4. Neurohypophysis.

Answer: 2. Gonadotrophs

Question 140. Hypothalamic Releasing Hormones Reach The Anterior Pituitary Gland By Way Of:

1. The Posterior Pituitary Gland
2. Lymphatic Vessels
3. Blood Vessels
4. Axons.

Answer: 3. Blood Vessels

Question 141. Excessive Production Of Growth Hormone During Adulthood Can Lead To :

1. A Pituitary Giant
2. A Pituitary Dwarf
3. Disproportionately Large Hands, Feet And Jaw
4. Deterioration Of The Bones.

Answer: 3. Disproportionately Large Hands, Feet And Jaw

Question 142. In Mammals, Prolactin Stimulates The Production Of :

1. Progesterone
2. Mucus In The Digestive Tract
3. Digestive Enzymes In The Small Intestine
4. Milk.

Answer: 4. Milk.

Question 143. Cushing’s Syndrome Is Associated With the:

1. Glucocorticosteroids
2. Mineralo Corticosteroids
3. Sex Corticosteroids
4. Gene Mutation.

Answer: 1. Glucocorticosteroids

Question 144. If A Person Is Subjected To Stress (Like Heat, Cold, Loud Noise, etc.) Continuously, Which Organ Will Undergo Hypertrophy :

1. Adrenal
2. Liver
3. Pancreas
4. Salivary Glands.

Answer: 1. Adrenal

Question 145. Addison’s Disease Is Caused By the:

1. Hyposecretion Of Corticosteroid
2. Oversecretion Of Corticosteroid
3. Hyposecretion Of Lh
4. Oversecretion Of Lh.

Answer: 1. Hyposecretion Of Corticosteroid

Neet Previous Year Questions On Endocrine System

Question 146. The Adrenal Glands Are Located Adjacent To The :

1. Larynx
2. Urinary Bladder
3. Kidneys
4. Gonads.

Answer: 3. Kidneys

Question 147. The Fight-Or-Flight Response Is Developed By Hormones Of The :

1. Hypothalamus
2. Adrenal Medulla
3. Adrenal Cortex
4. Adreno-Pancreatic Complex.

Answer: 2. Adrenal Medulla

Question 148. The Main Function Of Norepinephrine Is To Increase :

1. Blood Pressure
2. Urine Production
3. Cellular Respiration
4. The Release Of Epinephrine.

Answer: 1. Blood Pressure

Question 149. Epinephrine And Norepinephrine Function As Both Hormones And :

1. Fuel For Cellular Respiration
2. Neurotransmitters
3. Ions To Promote Action Potentials
4. Solutes To Promote Osmotic Flow.

Answer: 2. Neurotransmitters

Question 150. All The Hormones Of The Adrenal Cortex Are Synthesized From:

1. Tyrosine
2. Glycoproteins
3. Cholesterol
4. Fats.

Answer: 3. Cholesterol

Question 151. Disease Osteitis Fibrosa Cystica Is Related With :

1. Hyposecretion Of Parathyroid Hormone
2. Hypersecretion Of Parathyroid Hormone
3. Hypersecretion Of Mineralocorticosteroids
4. Hyposecretion Of Glucocorticosteroids.

Answer: 2. Hypersecretion Of Parathyroid Hormone

Question 152. The Part Of The Brain With the Greatest Influence Over The Endocrine System Is The :

1. Hypothalamus
2. Amygdala
3. Cerebral Cortex
4. Medulla Oblongata.

Answer: 1. Hypothalamus

Question 153. Which Of The Following Groups Of Arthropoda Has a Well-Developed Endocrine System?

1. Arachnida
2. Crustacea
3. Insecta
4. All Classes Of Arthropoda.

Answer: 4. All Classes Of Arthropoda.

Question 154. If Adenohypophysectomy Is Done In Adults, Then Which Of The Following Is The Correct Statement:

1. Acromegaly
2. It Will Affect the Function Of the Testis And Ovary
3. Gigantism
4. B.M.R. Will Be Affected.

Answer: 2. It Will Affect the Function Of the Testis And Ovary

Question 155. The Moult Of An Insect Is Triggered By :

1. Thyroxine
2. Ecdysone
3. Juvenile Hormone
4. A Pheromone.

Answer: 2. Ecdysone

Question 156. The Development Of Adult Characteristics In A Moulting Insect Is Promoted By :

1. Thyroxine
2. Ecdysone
3. Juvenile Hormone
4. A Pheromone.

Answer: 2. Ecdysone

Question 157. The Retention Of Larval Characteristics In A Moulting Insect Is Promoted By :

1. Thyroxine
2. Ecdysone
3. Juvenile Hormone
4. A Pheromone.

Answer: 3. Juvenile Hormone

Question 158. A Male Moth Finds A Mate Using:

1. Thyroxine
2. Ecdysone
3. Brain Hormone
4. Pheromone.

Answer: 4. Pheromone.

Question 159. Diabetes Mellitus Develops Only When :

1. α Cells Of the Pancreas Are In Excess
2. α Cells Of the Pancreas Are Not Functioning
3. β Cells Of Pancreas Are In Excess
4. β Cells Of the Pancreas Are Not Functioning.

Answer: 4. 3 Cells Of Pancreas Are Not Functioning

Question 160. The Target Cells Of A Hormone Always Have :

1. Special Receptors To Which The Hormone Binds
2. Special Channels Through Which The Hormone Moves
3. Large Amounts Of The Hormone Stored Within Vesicles
4. Undifferentiated Cytoplasm.

Answer: 1. Special Receptors To Which The Hormone Binds

Question 161. The Hormone Which Is Related To The Urine Concentration In Mammals :

1. Antidiuretic Hormone Only
2. Antidiuretic Hormone And Oxytocin
3. Antidiuretic Hormone And Aldosterone
4. Testosterone Only.

Answer: 3. Antidiuretic Hormone And Aldosterone

Neet Previous Year Questions On Endocrine System

Question 162. Which Of The Following Hormones Is A Steroid?

1. Prostaglandin
2. Estrogen
3. Epinephrine
4. Thyroxine.

Answer: 2. Estrogen

Question 163. In A Male Heavy Voice And Growth Of Beard And Moustaches Is Due To Oversecretion Of :

1. Androgen
2. Estrogen
3. Adrenaline
4. Estrogen And Progesterone.

Answer: 1. Androgen

Question 164. A Steroid Hormone Typically Alters The Activity Of Its Target Cells By :

1. Digesting Holes In The Cell’s Plasma Membrane
2. Entering The Cell And Altering Gene Expression
3. Passing Its Message To An Intracellular Messenger
4. Digesting Holes In The Cell’s Lysosomes.

Answer: 2. Entering The Cell And Altering Gene Expression

Question 165. Which Of The Following Hormones Is A Modified Amino Acid?

1. Prostaglandin
2. Estrogen
3. Epinephrine
4. Progesterone.

Answer: 3. Epinephrine

Question 166. A Peptide Hormone Typically Alters The Activity Of Its Target Cells By :

1. Digesting Holes In The Cell’s Plasma Membrane
2. Entering The Cell And Altering Gene Expression
3. Passing Its Message To An Intracellular Messenger
4. Digesting Holes In The Cell’s Lysosomes.

Answer:  3. Passing Its Message To An Intracellular Messenger

Question 167. Animal Tissues That Synthesize Hormones Are Closely Associated With, And Sometimes Resemble, Cells Of The :

1. Immune System
2. Embryonic Mesoderm
3. Circulatory System
4. Nervous System.

Answer: 4. Nervous System.

Question 168. Which One Of The following is Not Under Direct Control Of Pituitary Gland?

1. Adrenal Cortex
2. Adrenal Medulla
3. Thyroid
4. Testis.

Answer: 2. Adrenal Medulla

Question 169. If Thyroidectomy Of Tadpole Is Performed, Moulting Will Take Place :

1. Potassium Iodide Treatment
2. Fed On Adult Sheep Thyroid
3. Moulting Will Never Take Place
4. Normal Moulting Will Take Place.

Answer: 2. Fed On Adult Sheep Thyroid

Question 170. Spermatogenesis In the Mammalian Testis Is Controlled By :

1. FSH
2. LH
3. Progesterone
4. ICSH.

Answer: 1. FSH

Question 171. Vasopressin Is Related With :

1. Dilution Of Urine
2. Increased Heart Beat
3. Concentration Of Urine
4. Decreased Heart Beat.

Answer: 3. Concentration Of Urine

Question 172. The Part Of The Brain With The Greatest Influence Over The Endocrine System Is The :

1. Hypothalamus
2. Cerebellum
3. Cerebral Cortex
4. Medulla Oblongata.

Answer: 1. Hypothalamus

Question 173. Metabolic Rate In Mammals Is Controlled By :

1. Pancreas
2. Liver
3. Pituitary
4. Thyroid.

Answer: 4. Thyroid.

Question 174. Hypothalamo-Hypophyseal System Is Derived From :

1. Rathke’S Pouch
2. Neuroectoderm
3. Rathke’s Pouch And Neuroectoderm
4. None Of The Above.

Answer: 3. Rathke’s Pouch And Neuroectoderm

Question 175. The Cells Of the Pancreas That Produce Glucagon Are :

1. Alpha Cells
2. Gamma Cells
3. Acinar Cells
4. Beta Cells.

Answer: 1. Alpha Cells

Question 176. The First Hormone To Be Isolated (In 1902) Was :

1. Thyroxine
2. Testosterone
3. Epinephrine
4. Secretin.

Answer: 4. Secretin

Question 177. The Mammalian Thyroid Gland Is Located Adjacent To The

1. Adenoids
2. Trachea
3. Kidneys
4. Pancreas.

Answer: 2. Trachea

Question 178. Thyroxine And Triiodothyronine, Produced By The Thyroid Are Synthesized From Iodine And :

1. Phenylalanine
2. Cholesterol
3. Glycoproteins
4. Tyrosine.

Answer: 4. Tyrosine.

Pituitary Gland Hormones NEET Study Material

Question 179. The Parathyroid Glands Are Located Adjacent To The :

1. Adenoids
2. Thyroid Gland
3. Adrenal Glands
4. Pancreas.

Answer: 2. Thyroid Gland

Question 180. Progesterone Is Secreted By :

1. Corpora Allata
2. Corpus Albicans
3. Corpus Luteum
4. None Of These.

Answer: 3. Corpus Luteum

Question 181. Which Of The Following Statements is correct?

A. Endocrine Control Is Integrated With Neural Control At The Level Of The Hypothalamus.

B. Thyroid Hormones Are Required For Normal Prenatal Brain Development.

C. Glucocorticoids Are Anabolic Steroids.

D. Adrenal Medulla Releases Adrenaline And Noradrenaline In A Ratio Of Approximately 10:1:

Choose The Correct Answer

1. A And D
2. A And C
3. A And B
4. B And C

Answer: 3. A And B

Question 182. Which Of The Following Statement Is Correct?

1. Testosterone Is Not Water-Soluble And Acts Via Receptors On The Plasma Membrane Of The Target Cells.
2. Hypoglycemia Occurs Most Commonly In Diabetic Patients.
3. Oxytocin Is Released In Response To Mechanical Stimulation Of The Breast Nipple
4. Cellular Reactions Are Slow And More Accurate When Activity Is Determined By Two Antagonistic Hormones.

Answer: 2. Hypoglycemia Occurs Most Commonly In Diabetic Patients.

Question 183. The Posterior Pituitary :

1. Produces Oxytocin
2. Is Under The Control Of the Hypothalamic Releasing Neurohormone
3. Secretes Trophic Hormones
4. Secretes Neurohormones.

Answer: 1. Produces Oxytocin

Question 184. Parathyroid Hormone :

1. Is Produced By The Thyroid Gland
2. Is Released When Blood Calcium Levels Fall
3. Stimulates Osteoblasts To Lay Down New Bone
4. Stimulates Calcitonin Release.

Answer: 2. Is Released When Blood Calcium Levels Fall

Question 185. Steroid Hormones :

1. Have Only Cell Surface Receptors
2. Are Lipophobic
3. Act Through Altering The Activity Of Proteins In The Target Cell
4. Are Produced By The Adrenal Cortex.

Answer: 3. Act Through Altering The Activity Of Proteins In The Target Cell

Question 186. Match The Definitions Of Column 1 With the Appropriate Term Of Column 2

• A B C D E

1. 1 2 4 3 5
2. 5 1 2 3 4
3. 5 1 3 4 2
4. 5 1 2 4 3.

Answer: 2.  5 1 2 3 4

Question 187. Both Adrenaline And Cortisol Are Secreted In Response To Stress; Which Of The Following Statement Is Also True For Both Of These Hormones?

1. They Act To Increase Blood Glucose
2. They Are Secreted By The Adrenal Cortex
3. Their Secretion Is Stimulated By Adrenocorticotropin
4. They Are Secreted Into The Blood Within Seconds Of The Onset Of Stress.

Answer: 1. They Act To Increase Blood Glucose

Question 188. Which Of The Following Is Not Inhibitory Hormone?

1. PIH
2. GHIH
3. MIH
4. GI.

Answer: 4. GI.

Question 189. Melanocyte Stimulating Hormone Is Secreted By Which Cell Type Of Pituitary Gland?

1. Somatotroph
2. Thyrotroph
3. Corticotroph
4. Gonadotroph.

Answer: 3. Corticotroph

Question 190. Which Of The Following Can Cause the Release Of Oxytocin Hormone In A Lactating Mother?

1. Sight Of Baby
2. Sound Of Baby
3. Both 1 And 2
4. None Of Above.

Answer: 3. Both 1 And 2

Question 191. Which Of The Following Hormone Is Not Present In Both Sexes?

1. Oxytocin
2. ADH
3. FSH
4. ICSH.

Answer: 4. ICSH.

Question 192. About A Million Islets Of Langerhans Each With Approximately 3000 Cells Comprise What Percentage Of Pancreas?

1. 1
2. 1-5
3. 2
4. 2-5.

Answer: 2. 1-5

Question 193. Which Of The Following Statement Is Incorrect?

1. Somatostatin Inhibit The Secretion Of Insulin And Glucagon
2. Cortisol Hormone Has No Role During And After Danger
3. Hypoglycemic Results From Hypersecretion Of Insulin
4. Human Placental Lactogen Stimulate Mammary Growth.

Answer: 2. Cortisol Hormone Has No Role During And After Danger

Thyroid Gland Disorders NEET Exam Preparation

Question 194. Which Of The Following Is A Function Of Calcitonin?

1. Regulation Of Metabolic Rate
2. Maintenance Of Body Temperature
3. Regulate The Development Of Mental Faculties
4. All Of The Above.

Answer: 4. All Of Above.

Question 195. Hypophysectomy Results In Diminution Of All Except One Of The Following Hormones.

1. Acth (Adrenocorticotrophic Hormone)
2. Growth Hormone
3. Prolactin
4. Tsh (Thyroid Stimulating Hormone).

Answer: 3. Tsh (Thyroid Stimulating Hormone).

Question 196. The Glucocorticoids Are Mainly Responsible For :

1. Enhancement Of Glucose Formation
2. Diminution Of Glucose Formation
3. Excretion Of Sodium By Kidney
4. Retention Of Sodium By Kidney.

Answer: 1. Enhancement Of Glucose Formation

Question 197. Insulin Deficiency Produces :

1. Increased Entry Of Glucose Into Cells
2. Reduced Entry Of Glucose Into Cells
3. Decreased Release Of Glucose From Liver
4. No Effect On Carbohydrate Metabolism.

Answer: 2. Reduced Entry Of Glucose Into Cells

Question 198. Hormones Based On Fatty Acids Are :

1. Small In Size And Variable In Structure
2. Small In Size And Constant In Structure
3. Large In Size And Variable In Structure
4. Large In Size And Constant In Structure.

Answer: 2. Small In Size And Constant In Structure

Question 199. A Disease Which Is Caused By The Under-Secretion Of Adrenal Cortex Is :

1. Grave’s Disease
2. Addison’s Disease
3. Cushing’s Syndrome
4. Acromegaly.

Answer: 2. Addison’s Disease

Question 200. A Hormone Which Helps In The Implantation Of Embryo In Uterus Is :

1. Oestrogen
2. Relaxin
3. Progesterone
4. Thymosin.

Answer: 3. Progesterone

NEET Biology Endocrine System Questions From Competitive Examination

Question 1. Myxoedema Is Due To :

1. Decreased Production Of Thyroxine
2. Increased Production Of Thyroxine
3. Excess Gh
4. Decreased Insulin.

Answer: 1. Decreased Production Of Thyroxine

Question 2. Injection Of Glucagon Will :

1. Cause Hypoglycemia
2. Cause Galactosemia
3. Increase Blood Sugar
4. Cause Goitre.

Answer: 3. Increase Blood Sugar

Question 3. Goitre Influences :

1. Speech
2. Excretion
3. Metabolism
4. Vision.

Answer: 3. Metabolism

Question 4. Pheromones Are :

1. Produced By Endocrine Glands
2. Mrnas
3. Chemicals Used In Animal Communication
4. Proteins.

Answer: 3. Chemicals Used In Animal Communication

Question 5. Which Is Not Involved In Endocrine Secretion?

1. Ley Dig Cell
2. Lutein Cell
3. Para-Follicular Cells Of Thyroid
4. Kupffer Cells.

Answer: 4. Kupffer Cells

Neet Previous Year Questions On Endocrine System

Question 6. Gh Affects Growth By Controlling Production Of:

1. mRNA
2. tRNA
3. rRNA
4. None Of The Above.

Answer: 1. mRNA

Question 7. If the Receptor Molecule Is Removed From the Target Organ For Hormone Action, The Target Organ Will:

1. Continue To Respond But Requires Higher Concentration Of Hormone
2. Continue To Respond But In Opposite Way
3. Continue To Respond Without Any Difference
4. Not Respond To Hormone.

Answer: 4. Not Respond To Hormone.

Question 8. Melatonin Is Produced By :

1. Thymus
2. Skin
3. Pituitary
4. Pineal Gland.

Answer: 2. Skin

Question 9. On Seeing A Tiger, The Heart Beat And Blood Pressure Increase Due To Release Of Hormone :

1. Adrenaline
2. Thyroxine
3. Parathormone
4. Corticoids.

Answer: 2. Thyroxine

Question 10. A Person Has Protruding Eyes, Tachycardia, And Higher Body Temperature. He Is Suffering From :

1. Cretinism
2. Hyperthyroidism
3. Diabetes
4. Acromegaly.

Answer: 2. Hyperthyroidism

Question 11. Match The Endocrine Gland, Given Under Column 1 With Their Respective Position In The Body, Given Under Column 2. Choose The Answer Which Gives The Correct Combination Of Alphabets Of Two Columns :

1. A – S, B = T, C = P, D= Q
2. A = Q, B = S, C = T, D= P
3. A = T, B = R, C = P, D= Q
4. A = P, B = Q, C = R, D= T.

Answer: 3. A = T, B = R, C = P, D= Q

Question 12. Match The Hormone Listed Under Column 1 With The Roles  Given Under Column 2. Choose The Choice In Which The Alphabets Of The Two Columns Are Correctly Matched :

1. A = Q, B = S, C = P, D- R
2. A – T, B = P, C = S, D= Q
3. A = R, B = T, C = S, D= Q
4. A = T, B – S, C = P, D= Q.

Answer: 4. A = T, B – S, C = P, D= Q.

Question 13. Autoimmune Hypothyroidism Is :

1. Hashimoto Disease
2. Cushing Syndrome
3. Myxoedema
4. Addison’s Disease.

Answer: 1. Hashimoto Disease

Question 14. Steroids Are Precursors Of:

1. Progesterone
2. Oestrogen
3. Testosterone
4. All Of the Above.

Answer: 4. All Of Above

Thyroid Gland Disorders NEET Exam Preparation

Question 15. Thyrotropin – Releasing Factor (Trf) Is Produced By :

1. Cerebrum
2. Optic Lobe
3. Cerebellum
4. Hypothalamus.

Answer: 4. Hypothalamus.

Question 16. Tetany Is Caused By :

1. Hypothyroidism
2. Hyperthyroidism
3. Hypoparathyroidism
4. Hyperparathyroidism.

Answer: 3. Hypoparathyroidism

Question 17. Mainly Which Type Of Hormones Control The Menstrual Cycle In Human Beings :

1. FSH
2. Progesterone
3. FSH, LH, Estrogen
4. LH.

Answer: 3. FSH, LH, Estrogen

Question 18. When Both Ovaries Are Removed From the Rat Then Which Hormone Is Decreased In Blood?

1. Oxytocin
2. Gonadotrophic Releasing Factor
3. Estrogen
4. Prolactin.

Answer: 3. Estrogen

Question 19. Which One Of The Following Pairs Correctly Matches A Hormone With A Disease Resulting From Its Deficiency?

1. Insulin -Diabetes Insipidus
2. Relaxin -Gigantism
3. Prolactin -Cretinism
4. Parathyroid Hormone -Tetany.

Answer: 4. Parathyroid Hormone -Tetany

Question 20. Synthesis Of Testosterone By Leydig Cells Is Stimulated By :

1. FSH
2. ICSH
3. LTH
4. TSH

Answer: 2. ICSH

Question 21. Which One Of The Following Hormones Is A Modified Amino Acid?

1. Prostaglandin
2. Estrogens
3. Epinephrine
4. Progesterone.

Answer: 3. Epinephrine

Question 22. Which One Of The Following Pairs Correctly Matches A Hormone With A Disease Resulting From Its Deficiency?

1. Thyroxine-Tetany
2. Parathyroid Hormone-Diabetes Mellitus
3. Luteinizing Hormone-Failure Of Ovulation
4. Insuhn-Diabetes Insipidus.

Answer: 3. Luteinizing Hormone-Failure Of Ovulation

Question 23. Chemically The Hormones Are :

1. Proteins Only
2. Steroids Only
3. Biogenic Amines Only
4. Proteins, Steroids And Biogenic Amines.

Answer: 3. Biogenic Amines Only

Question 24. Which Of The Following Hormones Is Not A Secretion Product Of the Human Placenta?

1. Estrogens
2. Progesterone
3. Hcg
4. Prolactin.

Answer: 4. Prolactin.

Question 25. Damage To the Thymus In A Child May Lead To :

1. A Reduction In Haemoglobin Content Of Blood
2. A Reduction In Stem Cell Production
3. Loss Of Antibody-Mediated Immunity
4. Loss Of Cell-Mediated Immunity.

Answer: 4. Loss Of Cell-Mediated Immunity.

Question 26. Parkinson’s Disease (Characterized By Tremors And Progressive Rigidity Of Limbs) Is Caused By Degeneration Of Brain Neurons That Are Involved In Movement Control And Make Use Of Neurotransmitters:

1. Acetylcholine
2. Norepinephrine
3. Dopamine
4. Gaba.

Answer: 3. Dopamine

Question 27. Fsh Is Secreted By :

1. Anterior Lobe Of Pituitary
2. Hypothalamus
3. Gonads
4. Posterior Lobe Of Pituitary

Answer: 1. Anterior Lobe Of Pituitary

Question 28. Which One Of The Following Four Glands Is Correctly Matched With The Accompanying Description?

1. Thyroid – Hyperactivity In Young Children Causes Cretinism
2. Thymus – Starts Undergoing Atrophy After Puberty
3. Parathyroid – Secrete Parathormone Which Promotes the Movement Of Calcium Ions From Blood Into Bones During Calcification
4. Pancreas – Delta Cells Of The Islets Of Langerhans Secrete A Hormone That Stimulates Glycolysis In the Liver.

Answer: 2. Thymus – Starts Undergoing Atrophy After Puberty

Thyroid Gland Disorders NEET Exam Preparation

Question 29. The Hormone That Controls The Level Of Calcium And Phosphorus In The Blood Is Secreted By :

1. Thyroid
2. Parathyroid
3. Pituitary
4. Thymus.

Answer: 2. Parathyroid

Question 30. Which Of The Following diseases is Not Related To Thyroid Gland?

1. Myxoedema
2. Cretinism
3. Acromegaly
4. Goitre.

Answer: 3. Acromegaly

Question 31. Grave’s Disease Is Due To :

1. Hyperactivity Of the Thyroid Gland
2. Hypoactivity Of Adrenal Cortex
3. Hyperactivity Of the Adrenal Medulla
4. Hypoactivity Of Islets Of Langerhans.

Answer: 1. Hyperactivity Of Thyroid Gland

Question 32. Hassal’s Bodies/Corpuscles Are Found In :

1. Liver
2. Thymus
3. Thyroid
4. Adrenal.

Answer: 2. Thymus

Question 33. Choose The Correct Combination Of Labelling In The Hormonal Control Of the Female Reproductive System

1. A-GnRH, B-Tsh, C- Lth, D-Uterus
2. A-Gnrh, B-Fsh/Lh, C – Estrogen Of Progesterone, D- Utrerus
3. A-Gnrh, B-Sth, C-Lh, D-Uterus
4. A-Gnrh, B-Acth, C-Lh, D-Uterus.

Answer: 2. A-Gnrh, B-Fsh/Lh, C – Estrogen Of Progesterone, D- Utrerus

Question 34. Which Of The Following Is Not Paired Correctly?

1. Myxoedema – Swollen Facial Tissues
2. Cretinism – Mentally Retarded
3. Grave’s Disease – Exophthalmos
4. Insulin – Raise Blood Glucose.

Answer: 4. Insulin – Raise Blood Glucose.

Question 35. Match Item In Column 1 With Those Given In Column 2.

1. 1 – A, 2 – D, 3 – B,  4 – C, 5 – E
2. 1 – D, 2 – B, 3 – A,  4 – C,  5 – E
3. 1 – D, 2 – A, 3 – B,  4 – C,  5 – E
4. 1 – D, 2 – A, 3 – C,  4 – B,  5 – E.

Answer: 3. 1 – D, 2 – A, 3 – B,  4 – C,  5 – E

Question 36. If the Receptor Molecule Is Removed From the Target Organ For Hormone Action, The Target Organ Will:

1. Continue To Respond But Require Higher Concentration Of Hormone
2. Continue To Respond But In Opposite Away
3. Continue To Respond Without Any Difference
4. Not Respond To Hormone.

Answer: 4. Not Respond To Hormone.

Question 37. Match The List 1 Wish List 2

1. A : 3, B:1, C: 4, D: 2
2. A: 1, B: 2, C : 3, D: 4
3. A: 2, B: 1, C: 4, D : 3
4. A: 4, B : 3, C: 2, D: 1.

Answer: 3. A:2, B: 1, C: 4, D: 3

Question 38. A Patient Of Diabetes Mellitus excretes glucose In Urine Even When He Is Kept on a carbohydrate-free diet. It Is Because :

1. Fats Are Catabolised To Form Glucose
2. Amino Acids Are Catabolised In Liver
3. Amino Acids Are Discharged In Blood Stream From Liver
4. Glycogen From Muscles Are Released In The Blood  Stream.

Answer: 1. Fats Are Catabolised To Form Glucose

Question 39. Sertoli Cells Are Regulated By The Pituitary Known As:

1. Prolactin
2. LH
3. FSH
4. GH.

Answer: 3. FSH

Question 40. A Steroid Hormone Which Regulates Glucose Metabolism Is :

1. 11-Deoxycorticosterone
2. Cortisone
3. Cortisol
4. Corticosterone.

Answer: 3. Cortisol

Question 41. Which One Of The Following Is Not A Second Messenger In Hormone Action?

1. Sodium
2. Camp
3. Cgmp
4. Calcium.

Answer: 1. Sodium

Question 42. Which One Of The Following Statements Is Correct?

1. Neurons Regulate Endocrine Activity, But Not Vice Versa
2. Endocrine Glands Regulate Neural Activity, But Not Vice Versa
3. Neither Hormones Control Neural Activity Nor The Neurons Control Endocrine Activity
4. Endocrine Glands Regulate Neural Activity, And Nervous System Regulates Endocrine Glands.

Answer: 4. Endocrine Glands Regulate Neural Activity, And Nervous System Regulates Endocrine Glands.

Question 43. Which Hormone Causes Dilation Of Blood Vessels, Increased Oxygen Consumption And Glucogenesis?

1. Adrenalin
2. ACTH
3. Glucagon
4. Insulin.

Answer: 1. Adrenalin

Question 44. Withdrawal Of Which Of The Following Hormones Is The Immediate Cause Of Menstruation?

1. FSH
2. Progesterone
3. Estrogen
4. FSH-RH.

Answer: 2. Progesterone

Question 45. Which Is Not A Symptom Of Hypothyroidism?

1. Lethargy
2. Mental Retardation
3. Oedema
4. Rise In Blood Urea.

Answer: 4. Rise In Blood Urea

Question 46. Flyposecretion Of Which Of The Following Can Cause Diabetes Insipidus?

1. Insulin
2. Thyroxine
3. Glucagon
4. ADH.

Answer: 1. Insulin

Question 47. The Hormones That Initiate Ejection Of Milk, Stimulate Milk Production And Growth Of Ovarian Follicles Are Respectively Known As

1. PRL, OT, And LH
2. OT, PRL And FSH
3. LH, PRL, And FSH
4. PRH, OT, And LH
5. PRH, OT, And FSH

Answer: 2. OT, PRL And FSH

Question 48. Hypothyroidism In Adults And Hyperparathyroidism Will Respectively Lead To :

1. Myxoedema And Cretinism
2. Grave’s Disease And Hashimoto’s Disease
3. Myxoedema And Osteitis Fibrosa Cystica
4. Addison’s Disease And Cretinism
5. Cretinism And Osteitis Fibrosa Cystica.

Answer: 3. Myxoedema And Osteitis Fibrosa Cystica

Question 49. Which One Of The Following Endocrine glands functions As A Biological Clock And A Neurosecretory Transducer?

1. Adrenal Gland
2. Thyroid Gland
3. Pineal Gland
4. Thymus Gland
5. Pituitary Gland.

Answer: 3. Pineal Gland

Question 50. Match The Hormone In Column 1 With Their Function In Column 2.

1. A-5, B-4, C-L, D-2
2. A-4, B-5, C-2, D-1
3. A-4, B-3, C-2, D-5
4. A-5, B-1, C-2, D-4
5. A-4, B-2, C-3, D-5.

Answer: 1. A-5, B-4, C-1, D-2

Question 51. In The Homeostatic Control Of Blood Sugar Level, Which Organs Function Respectively As Modulator And Effector?

1. Liver And Islets Of Langerhans
2. Hypothalamus And Liver
3. Hypothalamus And Islets Of Langerhans
4. Islets Of Langerhans And Hypothalamus.

Answer: 3. Hypothalamus And Islets Of Langerhans

Question 52. Column 1 Lists The Endocrine Structure And Column 2 Lists The Corresponding Hormones. Match The Two Columns. Identify The Correct Option From Those Given.

1. P = t,  Q = r,  R = s,  S = q
2. P = t,  Q = r,  R = q,  S = s
3. P = p, Q = q, R = s,  S = r
4. P = r,  Q,= t,  R = s,  S = q.

Answer: 1. P = t, Q = r, R = s, S = q

Question 53. Which Of The Following Hormones Are Produced In The Hypothalamus And Stored In The Posterior Pituitary?

1. FSH And LH
2. ADH And Oxytocin
3. TSH And STH
4. ACTH and MSH.

Answer: 2. ADH And Oxytocin

Question 54. Parathyroid :

1. Increases Blood Ca Level
2. Decreases Blood Ca Level
3. Promotes Collagen Synthesis By Osteoblasts
4. All Of The Above.

Answer: 1. Increases Blood Ca Level

Question 55. Which Part Of the Ovary In Mammals Acts As An Endocrine Gland After Ovulation?

1. Stroma
2. Germinal Epithelium
3. Vitelline Membrane
4. Graffian Follicle.

Answer: 4. Graffian Follicle.

Question 56. A Person Is Having Problems With Calcium And Phosphorus Metabolism In His Body. Which One Of The Following Glands May Not Be Functioning Properly?

1. Parotid
2. Pancreas
3. Thyroid
4. Parathyroid.

Answer: 4. Parathyroid.

Question 57. Feeling The Tremors Of An Earthquake A Scared Resident Of the Seventh Floor Of A Multistoryed Building Starts Climbing Down The Stairs Rapidly. Which Hormone Initiated This Action?

1. Adrenaline
2. Glucagon
3. Gastrin
4. Thyroxine.

Answer: 1. Adrenaline

Question 58. Match List With List Ii And Select The Correct Option.

1. A – 2, B – 5, C – 4, D – 1, E – 3
2. A – 3, B – 4, C – 5, D -3,  E – 2 ‘
3. A – 5, B – 3, C – 2, D – 4, E – 1
4. A – 2, B -3,  C – 4, D – 5, E – 1
5. A – 5, B – 3, C – 4, D – 2, E – 1.

Answer: 1. A – 2, B – 5, C – 4, D – 1, E – 3

Question 59. Which One Of The Following Pairs Of Organs Includes Only The Endocrine Glands?

1. Thymus And Testes
2. Adrenal And Ovary
3. Parathyroid And Adrenal
4. Pancreas And Parathyroid.

Answer: 3. Parathyroid And Adrenal

Question 60. Which One Of The Following Is An Amine Hormone?

1. Insulin
2. Oxypurin
3. Thyroxine
4. Progesterone.

Answer: 3. Thyroxine

Question 61. The Blood Calcium Level Is Lowered By The Deficiency Of :

1. Thyroxine
2. Calcitonin
3. Parathormone
4. Both Calcitonin And Parathormone.

Answer: 3. Parathormone

Question 62. In Human Adult Females Oxytocin :

1. Is Secreted By the Anterior Pituitary
2. Stimulates Growth Of Mammary Glands
3. Stimulates Pituitary To Secrete Vasopressin
4. Causes Strong Uterine Contractions During Parturition.

Answer: 4. Causes Strong Uterine Contractions During Parturition.

Question 63. Match The Source Gland With Its Respective Hormone As Well As The Function.

Answer: 2. Posterior- Vasopressin- Stimulates resorption Of Water In the Distal tubules in the nephron

Question 64.  Given Below Is An Incomplete Table About Certain Hormones, Their Source Glands, And One Major Effect Of Each On The Body In Humans. Identify The Correct Option For The Three Blanks A, B, And C.

Answer: 1. A- Ovary, B- Glucagon, C- Growth Hormone

Question 65. Which One Of The Following Statements Is Incorrect?

1. Glucagon Is Secreted By Pancreas.
2. Androgen Is Produced By Ovary.
3. Thyroxine Is Secreted By Thyroid.
4. Oxytocin Is Secreted By the Pituitary.

Answer: 2. Androgen Is Produced By Ovary.

Question 66. Which Of The Following Statements Is Correct To The Endocrine System?

1. Organs In The Body Like the Gastrointestinal Tract, Heart, Kidney, And Liver Do Not Produce Any Hormones.
2. Non-Nutrient Chemicals Produced By The Body In Trace Amount That Act As Intercellular Messenger Are Known As Hormones.
3. Releasing And Inhibitory Hormones Are Produced By The Pituitary Gland.
4. Adenohypophysis Is Under Direct Neural Regulation Of The Hypothalamus.

Answer: 2. Non-Nutrient Chemicals Produced By The Body In Trace amounts that Act As Intercellular Messengers Are Known As Hormones.

Question 67. A Pregnant Female Delivers A Baby Who Suffers From Stunted Growth, Mental Retardation/Low Intelligence Quotient And Abnormal Skin. This Is The Result Of :

1. Low Secretion Of Growth Hormone
2. Cancer Of The Thyroid Gland
3. Oversecretion Of Pars Distalis
4. Deficiency Of Iodine In Diet.

Answer: 4. Deficiency Of Iodine In Diet.

68. Select The Answer Which Correctly Matches The Endocrine Gland With The Hormone It Secrets And Its Function/Deficiency Symptom :

Answer: 2.

NEET Biology Ecosystem

Ecosystem. The relationship between a living community (biotic) and its non-living environment (abiotic) is expressed by the term ecosystem. The term was introduced by Tansley (1937).

• Ecosystems are also called biocoenosis, geobiocoenosis, phytocoenosis, biosystem, exosome, and Holocene.
• Microecosystem. Very small-sized ecosystem.
• The Ecosystem is maintained by the flow of energy through it. This flow is unidirectional.
• Amount Of Energy Trapped. 2% of solar radiation by aquatic ecosystems.
• 1% of solar radiations by terrestrial ecosystems

Read and Learn More NEET Biology Notes

Ecosystem Notes For Neet

Bioenergetics. The flow of energy into ecosystems and its transformations in living organisms.

• Sun utilizes about 4 million tonnes of H₂ per second.
• Solar energy travels in space in the form of electromagnetic waves. Only 47% of solar radiation reaches the surface of the earth.
• Biomass. The amount of living matter present in an organism is biomass.
• The amount of biomass can be calculated in terms of energy.

NEET Biology Ecosystem

Components Of Ecosystem

Food Chains. A food chain consists of a connected group of producers, consumers, and decomposers. It starts with energy from the sun and nutrients from the soil. They pass through plants and one or several consumers to a final consumer that is not fed upon by any other.

Producers. They use the radiant energy of the sun during photosynthesis whereby CO₂ is assimilated and the light energy is converted into chemical energy. Green plants are called producers transducers or converters.

Autotrophs. They are green plants that have the capacity to synthesize food in sunlight. They are also called primary producers because solar energy is locked up only in these plants.

Heterotrophs. These are those organisms that are non-green and hence can’t manufacture their own food. Hence they have to depend upon other plants and animals for their food requirement. Hence they are consumers.

Primary Consumers. These are herbivorous animals and depend upon green plants i.e. on producers for their food, for example, Cows and goats.

Secondary Consumers. These are carnivorous animals and eat the flesh of herbivorous animals, for example, dogs, and cats.

Tertiary Consumers are the carnivorous animals that eat other carnivores for example, snakes eat frogs, birds, eat fish.

Top Consumers are carnivores of an ecosystem that are not killed and eaten by other animals, for example, Lions, Vultures, bears, etc.

Microconsumer. Decomposers are termed microconsumers.

Grazing Food Chain: The grazing food chain is also known as the predator food chain.

• In grazing food chains, the size of an individual gradually increases in successive trophic levels.
• Ecosystems with grazing food chains are directly dependent on solar radiation.
• Most of the ecosystems in nature follow the grazing food chain.

Detritus Food Chain: It starts from dead organic matter into microbes and then to detritus-feeding organisms (detritivores) and their predators. A good example of a detritus food chain is given by Heald and Odum.

The chain is based on mangrove (Rhizophore wangle) leaves, which fall into shallow estuarine waters of south Florida, leaf fragments acted on by saprotrophs and colonized by algae are eaten and re-eaten by a group of small detritus consumers which in turn, provide the main food for game fish and fish (small carnivore) eaten by birds (top carnivores).

• Dead plant parts and animal remains are called detritus.
• Dried plant parts such as leaves, bark, flowers, etc., and dead remains of animals including fecal matter dropped over the soil constitute the above-ground detritus or litter fall while dead roots (root detritus) constitute the below-ground detritus.
• In the detritus food chain source of energy is detritus (dead organic matter) and not the Sun.
• The detritus food chain is composed of a long chain of detritus-eating organisms (detritivores).
• In some ecosystems such as tropical rain forests, more energy flows in the detritus food chain than the grazing food chain.

Decomposers. These include bacteria, fungi, and other organisms that break down the complex compounds present in dead producers and consumers into simpler compounds. These simple organic matters are again decomposed by bacteria into inorganic forms.

Neet Biology Ecosystem Notes Pdf

Processes Of Decomposition

1. Fragmentation of detritus.
2. Leaching
3. Catabolism

1. Fragmentation. Due to fragmentation, the surface area of detritus particles is greatly increased.
2. Leaching. Water percolating through soil removes soluble substances (for example sugars, several nutrients) from the fragmented detritus due to leaching action.
3. Catabolism. The extracellular enzymes released by bacteria and fungi carry out catabolism i.e. enzymatic conversion of the decomposing detritus to simpler compounds and inorganic substances. It is important to know that all three decomposition processes operate simultaneously on the detritus.

Humification And Mineralization occur during decomposition in the soil. Humification leads to the accumulation of a dark-colored amorphous substance called humus. Humus is highly resistant to microbial action and undergoes extremely slow decomposition. It serves as a reservoir of nutrients. Mineralization results in the release of inorganic substances (for example CO₂, H₂O) and available nutrients (NH⁺₄, Ca⁺⁺, Mg⁺⁺, K^+, etc.) in the soil.

Factors Affecting The Rate Of Decomposition

1. The upper layer of soil is the main site of decomposition processes in the ecosystem.
2. The rate of decomposition of detritus is affected by climatic factors and the chemical quality of detritus.
3. Temperature and soil moisture affect the activities of root microbes.
4. The chemical quality of detritus is determined by the relative proportion of water-soluble substances, polyphenols, lignin, and nitrogen.

The amounts of energy and materials transferred from one trophic level to the next higher level become less and less and can be represented graphically as pyramids of energy and pyramids of biomass.

Abiotic Components. Abiotic components are non-living factors. It includes water, minerals, salts, humidity, light, temperature, pH, wind, topography, and background.

NEET Biology Ecosystem Food Web

Many food chains operate in a community. They are not independent but are interconnected to such an extent that disturbance in any food chain disturbs the whole community. The interrelationship among the various food chains of a community is called the food web.

When food chains are interconnected with each other forming a network of food transfer of energy flow. This network is called a food web.

The arrows in the figure indicate – the flow of energy which is always transferred but never exchanged.

Kinds Of Ecosystem

E. P. Odum classified ecosystem on the basis of photosynthesis-respiration ratio as under (P/R Ratio):

1. Stabilized Ecosystem: The P/R ratio is one.
2. Autotrophic Ecosystem: P/R is more than one.
3. Heterotrophic Ecosystem: The P/R ratio is less than one

NEET Biology Ecosystem General Pattern Of Energy Flow

Under favorable environmental conditions, only about 1-5% of the energy of incident radiation or 2-10% of PAR is actually captured by the photosynthetic process (gross primary productivity) and the remaining portion is dissipated.

Since the simultaneously occurring respiratory processes are energy-consuming and use up part of the photosynthetic gain, the net capture of energy (net primary productivity) is reduced to only 0-8—4% of the incident total radiation or 1-6-8% of PAR. Only the energy captured in the net productivity of producers can be used by other trophic levels.

NEET Biology Ecosystem Ecological Pyramids

Ecological Pyramids can be of three types:

1. Pyramid Of Number. It can be upright, inverted, or spindle-shaped.
   • Upright Pyramid. Grassland, Pond ecosystem
   • Spindle Pyramid. Forest ecosystem.
   • Inverted Pyramid. Parasitic ecosystem
2. Pyramid Of Biomass: It is upright for terrestrial habitats.
   • It is inverted or spindle-shaped for aquatic habitats where the biomass of a trophic level depends upon the reproductive potential and longevity of its members.
   • If the total biomass produced per unit of time is calculated, the pyramid of biomass shall always be upright.
   • Maximum biomass occurs in producers. About 10-20% of the biomass is transferred from one trophic level to another.
   • Upright-Pyramid. Grassland, Forest, and Parasitic ecosystems,
   • Inverted Pyramid. Pond ecosystem.
3. Pyramid Of Energy. Always upright, more accurate than the pyramid of biomass or the pyramid of numbers.

The energy content is expressed in kcal/ m²/ yr or kJ/ m²/yr.

Components Of Ecosystem Neet Notes

Energy Conserving Efficiency

• Grasslands: 1.15%
• Savannah: 0.9%
• Mixed Forests: 0.8%
• Modem Crops: 5%
• Sugarcane Field: 10-12%

1. Community Productivity. Rate of net synthesis of organic matter by a community per unit time and area.
2. Gross Primary Productivity. The total amount of food synthesized or biomass added by the organisms is called gross primary productivity.
3. Net Primary Productivity. The organism loses a part of this biomass during its metabolic activities. The net or balanced dry matter accumulated in the organism, after it has consumed a part of it in metabolism or respiration, is called Net Primary Productivity. It is also called assimilative photosynthesis.
   • Net primary productivity = Gross primary productivity – Biomass consumed in respiration.
4. Primary Productivity. The amount of energy accumulated through photosynthesis by producers is termed primary productivity.
5. Secondary Productivity. The rate of synthesis of organic matter by consumers is termed secondary productivity.
   • In one year one hectare of forest shall consume 30 tonnes of CO₂ and evolve 10 tonnes of O₂
   • The amount of carbon dioxide fixed annually through photosynthesis is 7 x 10¹³  kg.

NEET Biology Ecosystem NEET Biology EcosystemEcological Efficiency

It is the effectiveness with which it maintains its dynamic nature. It is expressed as the energy ratio, expressing the efficiency with which organisms exploit their food resources and convert the food into biomass.

• Such ratios are calculated by relating output to the input of energy, at various points along the pathway of energy flow.
• These ratios are multiplied by 100 to express in percentage

Photosynthetic Efficiency = Gross primary productivity/Total incident solar radiation x 100

Net Production Efficiency (NPE). The efficiency with which assimilated energy is incorporated into reproduction, growth, and storage, is called the net production efficiency. It may be shown as:

∴ NEP = Production (reproduction and growth)/Assimilation x 100

In plants, NPE is defined as the ratio of net to gross production. This varies, between 3085% depending on the habitat and growth pattern.

Gross Production Efficiency. The GPE is the product of the assimilation efficiency and net production efficiency.

∴ GPR = Assimilation efficiency x NPE = Production}/Ingestion

This represents the overall efficiency of biomass production within a trophic level.

Assimilation Efficiency. The entire food energy that is consumed is not assimilated. The assimilation efficiency is defined as the percentage expressing the proportion of ingested or consumed energy that is assimilated. It may be shown as:

∴ Assimilation Efficiency = \(\frac{\text{Assimilation}{Ingestion}}\) x 100

Herbivores assimilate about 60 to 70% of the energy in young vegetation and 80% of that in seeds.

Exploitation Efficiency. It is defined as the efficiency with which the biological production of an entire tropic level is consumed.

Components Of Ecosystem NEET Biology

∴ Exploitation efficiency = Ingestion of food/Prey production x 100,

Ecological Efficiency. The % of energy converted into biomass by a higher trophic level over the energy of food resources available at the lower trophic level is called ecological efficiency.

∴ Ecological Efficiency = Energy converted into biomass at tropic level/Energy present in biomass at lower trophic level x 100

Significance Of Ecological Efficiency:

The ratio is used to express the efficiency with which organisms exploit their food resources and convert the food into biomass. The ability of herbivores and carnivores to use the food energy ingested varies from one species to another.

NEET Biology Ecosystem Biomes

Biomes are large biogeographic areas characterized by the presence of distinct groups of climax vegetation, unique animals, and other forms of life.

Typical Climatic Conditions In Major Forest Types In India

• Temperate Deciduous Forests. The areas have warm summers and moderately cool winters. Rainfall is 75-150 cm. Dominant trees are Oak, Elm, Birch, Maple Ash, Chestnut, and chickory. Beech, Poplar, and Magnolia. Conifers occur at places. Shrubs, herbs, ferns, mosses, lichens, grasses, vines, and epiphytes are abundant.
  • Most trees shed their leaves during autumn or fall making the soil brown. A mixed coniferous broad-leaved forest occurs in Indian hills between 1500-3500 m. Tree height can reach 30-40 m. Fauna consists of Deer, Fox, and Beaver. Wild Cat. Racoon, Opossum, Squirrel, Rabbit, Hare, Snakes, Lizards, Salamanders. Thrushes, Owls, Sparrows, and songbirds.
• Taiga is the northern coniferous forest biome with long, severe winter and growing seasons limited largely to the few months of summer. Hardy conifers, Spruce in particular are the most representative of the flora and wolves and bears of the fauna.
• Grasslands Distribution. The temperate grasslands are present in North America (Canada and the USA), South America, Eastern Europe, Central Asia, South Africa, and Australia. These are called prairies in North America, pampas in South America, steppes in Europe and Asia, veldts in Africa, and tussocks in Australia.
  • Economic Importance. The grasslands are of tremendous economic importance, for they are the prime farming (grain-growing and cattle-raising). Overfarming and loss of topsoil are serious ecological problems that threaten food production.
  • Physical Conditions. The land is plain or gently rolling. The annual rainfall ranges between 25 to 75 cm and it rains intermittently. Moisture is not enough to support forest or woodland. The climate is cold in winter and hot in summer. Dry periods are long. The sunlight is bright and evaporation high.
• Life. Life is rich in the temperate grasslands.
  • Flora. The short and tall grasses, legumes, and composites form the dominant vegetation. Shrubs and trees may occur as scattered individuals.
  • Fauna. The animals of grasslands are grazing and burrowing mammals.
    • The grazing forms include bison, elk, prong-homed antelope, zebra, bighorn sheep, and deer. The burrowing forms are represented by rodents, such as jackrabbits, prairie dogs, gophers, and ground squirrels.
    • Carnivores, such as wolves, badger, coyotes, and many birds, such as lark, burrowing owl; and insects are also common. Some reptiles (lizards and snakes) also occur.

Characteristics Of Different Terrestrial Biome

Desert: It is a dry sandy or rocky area with sparse vegetation due to the occurrence of little rain. Rainfall is low less than 120 mm or extreme deserts less than 70 mm per year because the area lies in rain shadow.

This is due to being present either far away from cloud-seeding areas, adjacent to cold ocean currents, beyond a mountain range, or without cloud intercepting mountains. Common deserts are Tibet, Gobi (Mongolia), Thar (India, Pakistan), Arabia, and Sahara, Deserts may be cold deserts or hot deserts.

Hot Deserts: Fewer plants grow in deserts. They are of different ecological categories, ephemeral annuals, rain perennials, succulents, and non-succulent perennials. Succulent include Cacti and Euphorbias. In cold deserts, Sedum, Draba, and Saxifraga occur.

Non-succulent hot desert plants are Aerua, Alhagi, Capparis, Calotropis, Cyperus, Calligonum, Eragrostis, Acacia, Tamarix, Prosopis, and Phoenix. Desert animals live in burrows during the hot periods. Common animals are ants, wasps, locusts, scorpions, spiders, lizards, snakes, desert rats, rabbits, hares, foxes, jackals, cats, etc.

Neet Previous Year Questions On Ecosystem

NEET Biology Ecosystem Aquatic Biomes

Oceanic, Lakes And Ponds, Marshes, Streams And Rivers.

Oceanic Biome– 2/3 of earth’s surface, 3.5%-concentration of salts, productivity is 1000 kcal/m² yr (less than the most terrestrial biomes). Temperature of ocean surface-28°C in equatorial regions and 0°C near the poles.

Divided Into (Depending Upon The Availability Of Light):

1. Photic Or Euphotic Zone-upper 200 m layer of ocean.
2. Apliotic Zone-200-2000 m.
3. Abyssal Zone-dark zone, below 2000 m.
4. Oceanic Basin Is Differentiated Into Three Parts:
   • Continental– Shelf. Gradually sloping area of the seashore. Slope- 0.1° from coastline to 160 km in the sea.
   • Continental Slope. A slanting area connects the continental shelf to the oceanic floor. Slope 3-6°.
   • Ocean Floor. Horizontal bottom area of open sea. Normal depth-6000m to 10,000m.

Three Main Types Of Environmental Zones Of Oceanic Basin:

1. Littoral Zone-sea floor of continental shelf.
2. Benthonic Zone– sea floor along continental slope, aphotic and abyssal zone, further differentiated into
3. The Pelagic Zone, the water of the ocean, is further differentiated into Epipelagic, Mesopelagic, Bathypelagic, and Abyssopelagic.

Marine Organisms Are Classified According To The Region Of Their Activity.

1. Plankton. Passively drifted organisms in surface layers of water bodies (some workers restrict the term plankton for micro-organisms, they refer to other large-size planktons as Neuston)
2. Nekton, actively swim in surface and deep waters, phagotrophic.
3. Benthos. Organisms of the bottom.

The Oceanic Biome Is Divided Into Three Major Ecosystems:

1. Open Sea. the area beyond the continental shelf, divisible into photic, aphotic, and abyssal zones. Otherwise has 2 parts pelagic and benthoic.
2. Coastal Region. The area of the continental shelf is divisible into 3 parts-intertidal, littoral, and neritic. The intertidal region is exposed, neritic zone comprises the main water body of the area. Beaches belong to the intertidal zone. A highly productive part of the coastal region is the Coral Reef, formed by foraminiferans, calcareous algae, and calcareous skeletons of coelenterates (especially corals).
3. Estuary. The name of the coastal bay is formed by the tidal mouth of the river due to the mixing of fresh and seawater, there is a wide fluctuation of salinity 0.5-3.5%. Fluctuations of temperature also occur.

Lakes And Ponds. Stationary freshwater bodies that occur on land. Ponds are small, hollow size than one hectare, depth of less than 2 in. Lakes are larger and deeper. Actually, ponds arc natural or man-made depressions which get filled with rain or runoff water. Lakes develop due to:

1. As a result of glaciation,
2. Natural or man-made depressions get filled with H₂O.
3. Develop from main stream or river (oxbow lakes).

• Oligotrophic Lakes– deep, rocky sides, little circulation of nutrients, little biota, for example, Sambhar Lake of Rajasthan.
• Eutrophic Lakes are rich in biota, quick circulation of nutrients, and shallower, for example, Dal Lake of Kashmir.
• Marshes -wetlands possessing turbid water bodies of a few cm in depth. Water received from rains and drains. Typical flora consists of amphibians and emerged hydrophytes named heliophytes. Snails, mosquitoes, larvae, insects, frogs etc occur.
• Streams And Rivers – Lotic Ecosystems – flowing fresh water which differs in physical and climatic conditions, O₂ content, temperature, speed, and volume of H₂O.
• Agroecology-Study of interrelationships between agricultural crops and their surrounding animate as well as inanimate environments.

Ecosystems do not occur in isolation, are in contact with adjacent ecosystems, and a part of their area overlaps (the overlapping area is called a Transition zone). Polar bear shows hibernation during winter in caves.

• Microscopic Phytoplanktons-diatoms, Chlamydomonas, chlorella, spirogyra.
• Freely Floating Plants – Lemna, Azolla, Pistia, Eichhomia.
• Suspended Macrophytes – Utricularia, Hydrilla.
• Anchored Submerged Plants – Vallisneria.
• Floating Leaned Anchored Plants – Nelumbo, Nymphaea.
• Emerged Plants – rooted at the bottom but part of them comes out of water. Sagittaria, Typha, Sciipus, Phragmites.

[All of the above varieties of plants are present in ponds and lakes]

Neet Previous Year Questions On Ecosystem

Aquatic Biomes Memory Points

• The word “Biocoenosis” was introduced by Carl Mobius.
• The Earth Summit in Rio de Janeiro focused on the conservation of genetic resources of flora and fauna.
• The flora of Delhi is predominantly xerophytic.
• Resurrection plants – examples of drought evasion Selaginella lepidophylla.
• Fecundity refers to the potential ability of an organism to generate reproductive units, including eggs, sperm, or asexual structures.
• Association. A collection of species within a trophic level use a shared resource base in a comparable manner, such as nectar-feeding birds or grazing and browsing mammals.
• Herbivores are sometimes referred to as Key Industry Animals. (Elton, 1927) due to their ability to transform plant materials into animal matter.
• Chaparral vegetation comprises resilient, dense, broad-leaved evergreen plants, such as sage and oak, that exhibit fire resistance.
• Illumination is severely deficient in the tundra, with winter temperatures ranging from -30°C to -40°C. Summer lasts around 60 days at a temperature of 10°C.

NEET Biology Ecosystem Vegetation Of India

In India, there are two most common types of plant formations.

Forests. Indian forests are classified into four major types based on temperature such as tropical, mountain subtropical, temperate, and alpine.

1. Tropical forests. They are of two types moist and dry. Moist tropical forests. On the basis of the degree of wetness, they may be
   • Tropical Wet Evergreen Forests. Annual rainfall is over 250 cm. as in the West Coast, Assam, Bengal, and Andaman islands. The dominant trees arc Dipterocarpus, Hopea, Artocarpus, Emblica, Man gif era, Iscora, and some climbers (Lianas) and epiphytes.
   • Tropical Moist Semi-Evergreen Forests. They are found in North Assam, Bengal, parts of Orissa receiving heavy rainfall. Trees shed their leaves for a brief period. They include trees such as Terminalia; and Shorca.
   • Tropical Moist Deciduous Forests. They are common in moist areas of Kerala, Karnataka, South Madhya Pradesh, Northern Uttar Pradesh, and Bihar. Bengal and North Orissa. They include teak and Sal trees.
   • Dry Tropical Deciduous Forests. Trees remain leafless for several weeks in the dry season. Trees are moderate in size with sparse canopy. Thorny shrubs, grasses, and some bamboos are also present in some regions. In the north, such forests are found in Punjab, U.P. Bihar, and Orissa in regions that are neither wet nor too dry.
2. Temperate Forests. They occur above 5,300 ft altitude, chiefly in the mountains of the Himalayas and Nilgiri. In the Himalayas, Oaks and conifers are abundant.
3. Alpine Vegetation. They are extensive throughout the Himalayas above 11,000 ft. The tree’s height becomes lesser with increasing altitude. Alpine vegetation is characterized by Rhododendrons. It includes small plants like Sedum, Primula, Saxifraga, and lichens.
4. Grasslands. In India, natural grasslands are not found. Most Indian grasslands are being maintained in their present serai stage due to biotic interference.

NEET Biology Ecosystem Biosphere

Biosphere. The inhabited part of the earth and its atmosphere form the biosphere. It extends to about 22.5 km in thickness from the ocean bottom to the mountain tops.

• Maximum Density Of Organisms is found in coral reefs and tropical rain forests.
• Pedosphere. Consists of soil.
• The lithosphere is the dry crust of the earth (rocks and soil) 20 km in thickness.
• Hydrosphere. Oceans and sea (70% of the total earth’s surface).
• The atmosphere consists of 78% N₂, 20.9% 02, 0.94% Ar, and 0.03% CO₂.

The atmosphere is differentiated into the troposphere, stratosphere, ozonosphere, and ionosphere.

NEET Biology Ecosystem Ecological Succession

Biotic Succession. A biologically controlled modification in the composition of a community of a particular area is called biotic succession or ecological succession. Biotic succession is also known as the successive development of different communities in a particular area till a climax community is formed.

It was first studied by King (1685). The term succession was coined by Hult(1885). Clements defined it as a natural process by which the same locality becomes successively colonized by different groups of plants. Odum further described it.

Energy Flow In Ecosystem NEET Study Material

Kinds Of Succession

1. Primary Succession (Prisere). In any of the basic environments, primary succession starts from the primitive substratum, where there was no previously any sort of living matter. The first group of plants established there are known as pioneers, primary community, or primary colonizers and the last group is of climax community formed of tall trees.
   • The time taken for the development of forest climax or sand-dune or barren land is about 1000 yrs. Time taken is about 50-100 yrs in the case of grassland and more than 200 yrs for a forest
2. Autotrophic Succession. This type of succession is dominated by autotrophs which represent the first serial stage. lt occurs on a substratum having excess mineral matter but little organic matter.
3. Heterotrophic Succession. It occurs on a substratum having an excess of organic matter. This type of succession is always dominated by detrivores i.e., fungi and bacteria.
4. Induced Succession. It occurs due to extensive external interference. Here the initial community has high productivity which gradually decreases. The agriculture can be deemed as an example of induced succession.
   • Here a steady state is maintained for an ultimate good harvest. Elimination of weeds can be deemed as a step towards retrogression as it inhibits the arrival of a stable state.
5. Autogenic Succession. When the plants themselves gradually modify the environment to the extent that the habitat itself becomes unfavorable for the existing vegetation, a new type of succession starts. The old communities disappear and new ones come up for whom the environment is more suitable. This has been described as autogenic succession.
6. Allogenic Succession. The habitat may change due to external thrust i.e. of the environment. The succession taking place on account of this is called as allogenic.
7. Retrogressive Succession. Due to environmental thrust and human interference the climax vegetation may retrograde into shrubland or savannah. This is referred to as retrogressive succession.
8. Deflated Succession. When the succession doesn’t proceed through its normal course and sidetracks the advancement line, it is called as deflated succession. If the normal stages are 1 → 2 → 3 → 4 and the succession occurs as 1 → 2 → 3A → 3B → 4 is deflated.
9. Cyclic Succession. It occurs within the normal discourse of succession. If at a certain stage, the normal succession line is substituted by repetition of a previous stage due to external thrust, the succession is called cyclic for example 1 → 2 ⇔ 3 → 4.

Causes Of Succession

1. Initiation.
   • Physiographic factors include erosion, deposition, submergence, and emergence.
   • Climatic Factors produce secondary, barren areas including wind, water, snow, hail, re, and draught.
   • Biotic Factors produce secondary barren areas including animals, mankind, and microorganisms.
2. Continuation. Once started succession continues
3. Stabilization

Process Of Succession: The various stages are

1. Nudation
2. Migration
3. Ecesis
4. Aggregation
5. Competition
6. Co-action
7. Reaction and
8. Stabilization.

Secondary Succession Subsere. It occurs when an early community has been damaged leaving a few organisms and considerable organic matter.

• Ecological Succession in dry habitats, bare rock, sandy soil, and aquatic habitats are respectively called Xerosere, lithosere, psammosere, and hydrosere.
• In hydrosere (or hydrarch), pioneers in an ecological succession are submerged hydrophytes.
• In lithosere, the pioneers in an ecological succession are crustose (Saxicaulous lichens, Graphis, Rhijocaibon).
• The dominant species are different for each succession stage in the series.
• The last succession in a series is called the climatic climax or climax.

Energy Flow In Ecosystem NEET Study Material

NEET Biology Ecosystem Different Stages In Hydrosere With Component Plants

Phytoplankton Stage: (blue-green and green algae pioneer, Diatoms, bacteria.)

Rooted submerged Stage: Hydrilla, Vallisnaria Utricularia, Potamogeton Elodea, Najas, Ceratophyllum, certain got volume crunch as choro ano Nitalla

Floating Stage: Nelumbo, Nymphala, Zolle hemna, Trapa

Reed Swamp Stage: (Typha, Sagittaria Phragmites, Sagittaria, Siripus (Amphibious stage)

Sedge Meadow Stage: (Cyperus, Juncus, Eleocharis, Carix)

Wood Land Stage: (Salix, Populus, Alnus) (Climax community) Forest stage (Temperate mixed tropical rain and tropical deciduous)

NEET Biology Ecosystem Different Stages In Xerosere With Component Plants

NEET Biology Ecosystem Differences Between Terrestrial And Aquatic Succession

NEET Biology Ecosystem Differences Between The Seral And Climax Community During Succession

Dominance of a species:

Any one or more species is present in a majority during succession in every stage, and that species is the dominant species in the community. For instance, a location may be classified according to the species that predominate the region, such as a teak forest or pine forest.

The dominant species significantly influences the community and the surrounding environment. At any stage, it is not requisite for a single species to dominate; multiple species may coexist in dominance. For example, in the rainforests of tropical regions, 10 to 12 species dominate.

NEET Biology Ecosystem Biogeochemical Cycle

The circular paths of the chemical elements between organisms and the environment are known as biochemical cycles.

Cycles of material are classified into gaseous and sedimentary cycles,

1. For Gaseous cycles, the reservoir of materials is the atmosphere or water. The four major elements in living organisms: carbon, hydrogen, oxygen, and nitrogen, are predominantly gaseous;
2. In the Sedimentary cycle involving minerals, like phosphorus, sulfur, and calcium, the reservoir is the lithosphere.

Energy Flow In Ecosystem NEET Study Material

Oxygen Cycle: The oxides can be reduced both chemically as well as biologically to produce oxygen. Microbial oxidation can also occur. O₂ content of the atmosphere has remained constant for the last several million years.

Most of the O₂ lost is replenished by photosynthesis.

Greenhouse gases tire (CO₂ CH₄, dust, HO₂, NO₂, SO₂) are transparent to incoming solar radiations but are strong absorbers of long wave or infrared radiations emitted by the earth’s surface.

Carbon Cycle: The three main sources of carbon in the non-living world are:

1. CO₂ of air as well as dissolved in water
2. Carbonates of rocks in the earth’s crust
3. Coal and petroleum of fossil fuels.

Most CO₂ enters the living world through photosynthesis.

• The amount of carbon fixed by photosynthesis is 7 x 10¹³ kg per year.
• One hectare of healthy forest produces about 10 tonnes of O₂ and absorbs 30 tonnes of CO₂ every year.

Nitrogen Cycle: N₂ forms 4/5 part of the atmosphere; picked up as inorganic compounds by plants and some prokaryotes (NO^–₃ and NH₄) and converted into organic N₂.

N₂ Fixation Is Of Three Types

1. Atmospheric-electrochemical and photochemical reactions (35 mg/ m²/ yr).

2. Biological by free-living bacteria (Azotobacter, Clostridium), symbiotic bacteria (Rhizobium), and cyanobacteria (Anabaena, Nostoc) [140-700 mg/m²/yr].

Proteins (Nitrogenous Compounds)

Ammonifying bacteria are Bacillus vulgaris and Bacillus remosa.

Dead bodies of plants and animals also contain nitrogenous compounds, for example, Bacillus, actinomycetes, and fungi.

3. Industrial – Haber’s process

Water Cycle: 60-90% of the body weight of an organism is made up of water.

• The water or hydrological cycle is actually made up of two overlapping cycles: Larger ‘global’ and smaller ‘local’
• Precipitation is of three main types. Rain, Snow, and Hail.
• The total world precipitation amounts to 4.46 x 10²⁰ G per year. (1G = 10²⁰ gm).
• Biogeochemical Cycle. The cycling of materials between living and non-living components of the biosphere is called the biogeochemical cycle.

Phosphorus Cycle: The atmospheric or gaseous cycle for phosphorus is absent. Guano (excreta of marine birds) is a good source of phosphorus.

Sulfur Cycle: In the sulfur cycle, the gaseous phase is reduced. In nature, sulfur occurs in the elemental form (as metal sulfides and sulfates) and some amount as SO₂ gas.

• Sulfur is available to plants as sulfate
• Sulfur is available to plants as sulfate. (SO₄^2-) ions which are produced by the oxidation of exposed acid eroded rock surfaces. Most of this oxidation is biological and is carried out by specialized bacteria which derive energy from the process.
• In plants, absorbed SO₄^2- ions are incorporated into the thiol (-SH) groups of amino acids and proteins. In this form, the sulfur passes through the various trophic levels being released from living organisms only as a constituent of feces.
• Decomposing bacteria break down the protein of dead organisms, reducing the -SH groups to H₂S (hydrogen sulfide). It is the presence of this gas that sometimes gives the characteristic odor of rotten eggs to decomposing matter. The H₂S produced may be oxidized to SO₄^2- by certain bacteria but this is only possible under aerobic conditions.
• Specialized photosynthetic bacteria living in sulfur springs use H₂S instead of H₂O as a raw material in the manufacture of carbohydrates and this sulfur returns to earth’s sediments.

Calcium, Magnesium, And Other Minerals: They are also cycled like other materials. These elements are slowly released from the rocks by the action of water and wind. These are either blown into the air as dust or are absorbed by plants through their roots.

Some organisms, such as mollusks and corals, deposit a substantial quantity of calcium in their shells and skeletons that are not available for quick cycling.

• The vertical distribution of different species occupying different levels is called stratification
• Components of the ecosystem are seen to function as a unit with the following consideration

Ecosystem Notes For Neet

Productivity

• Gross Primary Productivity (GPP)
• Net Primary Productivity (GDP)
• Secondary Productivity

Primary Productivity Depends Upon:

• Plant species Environmental factors
• Availability of nutrients
• Photosynthetic capacity

Decomposition. Steps: Fragmentation, Leaching, Catabolism, Humification, Mineralization (Temperature, Soil moisture, Oxygen and detritus composition regulate decomposition,

Energy Flow: Producers → Primary → Secondary

• Detritus Food Chain (DFC)
• Grazing Food Chain (GFC)

Food Web. The natural interaction of food chains makes the food web.

• The number of trophic levels is restricted as the transfer of energy follows 10 percent law Ecological pyramids
• The pyramid of energy is always upright
• The pyramid of number and biomass is generally upright
• The pyramid of biomass in the sea is generally inverted
• The pyramid of biomass of a small standing crop of phytoplankton supports a large standing crop of zooplankton thus it is inverted.

NEET Biology Ecosystem Ecosystem Synopsis

The deep sea constitutes an incomplete ecosystem due to the absence of producers. Koala bears are monophagous and will perish in the absence of eucalyptus leaves.

• The pH of oceans exhibits minimal variation.
• Snails and earthworms are absent in acidic soils.
• Euglena and other flagellates are prevalent in acidic aquatic environments.
• Organisms with calcareous shells inhabit environments with neutral or alkaline pH levels.
• Snails inhabit soils abundant in calcium.
• Animals counteract seawater salinity via salt-secreting glands.
• Terrestrial animals are unaffected by alterations in pH levels. Nonetheless, it dictates the distribution of terrestrial flora and edaphic creatures.
• Sloths are exclusively arboreal in their environment.
• Some creatures function as both producers and consumers, such as insectivorous plants like Nepenthes (pitcher plant) and Drosera (Sundew plant).
• Omnivores such as humans and bears occupy multiple trophic levels.

Ecological equivalents. Animals occupying similar ecological niches (similar food) in different geographical areas for example both owls and cats feed upon shrews and rats in woodland areas and near human habitations respectively.

• There is the highest species diversity in the Tropical rainforest ecosystem.
• Gujarat has the largest number of salt lakes in India.
• Brine is water that has a high concentration of salt.
• Herbs other than grass are called forb.
• The number of biomes on a mountain range decreases with the increase in the latitude of the mountain.
• Brackish lakes are always oligotrophic for example Sambhar Lake of Rajasthan.
• Detritus trophic level – The last trophic level is constituted by decomposers.
• Detritivores are decomposers as well as scavengers.

The detritus food chain is the shortest. Dystrophic lakes are rich in bogs (undecomposed organic matter), poor in CaCO₂ and other inorganic matter, and poor in oxygen for example marshy lakes.

• With increasing dependence on animal diets, the human population will need more farm produce.
• Britain receives 2500 cal/cm²/yr of solar radiation while the amount at Varanasi in India is 75000 cal/ cm²/yr.
• The fish ‘Hilsa’ is found in both fresh and marine waters.
• Gauses hypothesis or Principle of competitive exclusion.
• No two species can occupy the same ecological niche. In case it happens, only one survives while the other is excluded.
• Tropical region occurs between 23°N and 23°S.
• Secchi disc is used in measuring turbidity.

Plagiosere. It is a deflected sere where plant succession deviates from its natural course due to human activity and other forms of external intervention.

• The climax of plagiosere is known as plagioclimax or disclimax.
• The daily tidal cycle recurs after every 12.4 hours.
• Characteristic vegetation beyond the timberline is Elfin scrub and Alpine meadows.
• The water cycle is made up of two overlapping cycles — larger global and smaller local.
• Matter occupies a space. It can be seen, smelled, tasted, and touched while energy does not occupy space and it can be felt through specific receptors for example heat, sound, light.
• Earth is a closed system as far as materials are concerned.
• Beijerinck (1888) isolated Bacillus radicicola and showed its ability to produce root nodules.
• Winogradsky (1891) discovered nitrogen fixation.
• Sea birds excrete uric acid, which is deposited to form guano in littoral islands. It is rich in uric acid and phosphorus and used as fertilizer.

Ozone-depleting gases are on NO₂ (6%) chloroform carbons (25%) halocarbon/halons, and CO₂ (57%)

Ecosystem Notes For Neet

Differences Between Grazing And Detritus Food Chains

Differences Between Wet Deposition And Dry Deposition

The Ecosystem Receives Nutrients By

1. Wet deposition
2. Dry deposition

NEET Biology Ecosystem Multiple Choice Questions And Answers

Question 1. The term ecosystem was coined by:

1. Sukachey
2. Vernadsky
3. Haeckel
4. Tansley.

Answer: 4. Tansley.

Question 2. Biotic components of an ecosystem include:

1. Producers
2. Consumers
3. Decomposers
4. All the above.

Answer: 4. All the above.

Question 3. Which is the most stable ecosystem?

1. Mountain
2. Desert
3. Forest
4. Ocean.

Answer: 4. Ocean.

Question 4. In a biotic community, primary consumers are:

1. Omnivores
2. Carnivores
3. Detritivores
4. Herbivores.

Answer: 4. Herbivores.

Question 5. If we completely remove the decomposers from an ecosystem, the ecosystem functioning will be adversely affected because:

1. Mineral movement will be blocked
2. Herbivores will not receive solar energy
3. Energy flow will be blocked
4. The rate of decomposition of another component will be very high.

Answer: 1. Mineral movement will be blocked

Question 6. The food chain will end with:

1. Carnivores
2. Herbivores
3. Decomposers
4. Secondary carnivores.

Answer: 4. Secondary carnivores.

Question 7. Which of the following is a way flow rather than a two-way or cyclic flow?

1. Carbon
2. Nitrogen
3. Potassium
4. Free energy.

Answer: 4. Free energy.

Components Of Ecosystem Neet Notes

Question 8. The importance of the ecosystem lies in:

1. Flow of energy
2. Cycling of materials
3. Both (1) and (2)
4. None of the above.

Answer: 3. Both (1) and (2)

Question 9. The driving force for an ecosystem is:

1. Biomass
2. Producers
3. Food
4. Solar Energy.

Answer: 4. Solar Energy.

Question 10. About how much of solar energy that falls on the leaves of a plant is converted to chemical energy by photosynthesis?

1. 1%
2. 10%
3. 30%
4. 50%.

Answer: 1. 1%

Question 11. Energy and nutrients enter a community by way of:

1. Producers
2. Consumers
3. Scavengers
4. Detritivores.

Answer: 1. Producers

Question 12. A consumer whose carbon atoms have already passed through three species is a:

1. Scavenger
2. Tertiary Producers
3. Tertiary Consumers
4. Secondary Consumers.

Answer: 3. Tertiary Consumers

Question 13. The average annual precipitation in a desert biome is:

1. 15-25 cm
2. 25-30 cm
3. 50-75 cm
4. 75-100 cm.

Answer: 1. 15-25 cm

Question 14. A sequence of species through which the organic molecules in a community pass is called:

1. Pyramid of energy
2. Food chain
3. Food web
4. Nutrient cycle.

Answer: 2. Food chain

Question 15. Savannahs are:

1. Tropical rain forest
2. Desert scrubs
3. Grassland with scattered trees
4. Dense forests.

Answer: 3. Grassland with scattered trees

Components Of Ecosystem Neet Notes

Question 16. Most food chains are composed of:

1. 1 or 2 species
2. 3 or 4 species
3. 9 or 10 species
4. More than 16 species.

Answer: 2. 3 or 4 species

Question 17. A micro-climate is controlled mostly by factors associated with:

1. The flatness of the terrain
2. Vegetation
3. Latitude
4. Longitude.

Answer: 3. Latitude

Question 18. In which of the following habitats does the diurnal temperature of soil surface vary most?

1. Desert
2. Grassland
3. Shrubland
4. Forest.

Answer: 1. Desert

Question 19. A biome with high temperature, high rainfall no seasonal change, and soil rich in minerals and humus is:

1. Shrub land
2. Coral reef
3. Tropical rain forest
4. Temperate evergreen forest.

Answer: 3. Tropical rainforest

Question 20. A plant eaten by herbivorous animals which in turn is eaten by a carnivorous animal, it forms a:

1. Food chain
2. Food web
3. Food pyramid
4. Biotic potential.

Answer: 1. Food chain

Question 21. A pond is a:

1. Biome
2. Agro-ecosystem
3. Natural ecosystem
4. Community.

Answer: 3. Natural ecosystem

Question 22. Which of the following communities would have trees?

1. Taiga
2. Littoral zone
3. Shrub land
4. Tundra.

Answer: 1. Taiga

Question 23. Which of the following has a vegetation structure with only one level?

1. Tropical rain forest
2. Taiga
3. Grassland
4. Shrub land.

Answer: 3. Grassland

Question 24. What type of pyramids are commonly referred to in ecological studies?

1. Lateral
2. Compound
3. Upright
4. Inverted.

Answer: 3. Upright

Question 25. Which type of system does the earth along with its atmosphere constitute?

1. Open
2. Closed system
3. Cut off system
4. Biogeochemical system.

Answer: 2. Closed system

Question 26. Enrichment of habitat (say pond) with nutrients is called:

1. BOD
2. Biological magnification
3. Eutrophication
4. Autopurification.

Answer: 3. Eutrophication

Question 27. Wolves and lions may be said to occupy the same trophic level because:

1. They both eat primary consumers
2. They both utilize their food with about 10% efficiency
3. They both live in a pond
4. Both are large mammals.

Answer: 1. They both eat primary consumers

Question 28. About how much of the chemical energy within the producer’s tissue becomes chemical energy within herbivore tissue.

1. 1%
2. 10%
3. 30%
4. 50%.

Answer: 2. 10%

Question 29. The most diverse oceanic communities are in the:

1. Abyssal zone
2. Littoral zone
3. Neritic zone
4. Oceanic zone.

Answer: 2. Littoral zone

Components Of Ecosystem Neet Notes

Question 30. Which of the following aquatic ecosystems has very little primary productivity?

1. River
2. Estuary
3. Lake
4. Marsh.

Answer: 1. River

Question 31. Which of the following statements is true about ecological relationships?

1. Competition with members of other species is more severe than that with one’s own species
2. Competition with members of other species is less severe than with one’s own species
3. Competition with members of other species is as severe as that with one’s own species
4. Competition does not exist between members of different species.

Answer: 2. Competition with members of other species is less severe than with one’s own species

Question 32. The above represents:

1. Food chain
2. Food web
3. A population
4. Ecosystem.

Answer: 2. Food web

Question 33. Light compensation zone refers to the zone:

1. Where all light energy is used efficiently
2. Where light is available
3. Beyond which light does not penetrate
4. Where light is maximum.

Answer: 3. Beyond which light does not penetrate

Question 34. Aquatic ecosystem covers how much of the earth’s surface?

1. 87%
2. 23%
3. 72%
4. 49%.

Answer: 3. 72%

Question 35. A biome with high temperature, and high rainfall is:

1. Shrub land
2. Coral reef
3. Semi-desert scrub
4. Tropical rain forest.

Answer: 4. Tropical rainforest.

Question 36. The importance of the ecosystem lies in:

1. Cycling of materials
2. Flow of materials
3. Both of the above
4. None of the above.

Answer: 3. Both of the above

Question 37. What are biotic components?

1. The living components
2. The non-living components
3. Both living and non-living
4. None of the above.

Answer: 1. The living components

Question 38. The flora and fauna in lakes and ponds are;

1. Lentic biota
2. Lotic biota
3. Abiotic
4. None of the above.

Answer: 1. Lentic biota

Question 39. The source of energy in an ecosystem is:

1. The heat from the soil
2. Heat reflected by leaves
3. Burning of sugar
4. Sunlight is received by leaves.

Answer: 4. Sunlight received by leaves.

Components Of Ecosystem Neet Notes

Question 40. The energy storage at the consumer level is called:

1. Gross primary productivity
2. Secondary productivity
3. Net primary productivity
4. Net productivity.

Answer: 2. Secondary productivity

Question 41. The hardest competition for food, light, and space is seen in:

1. Closely related species growing in the same niche
2. Closely related species growing in different habitats
3. Distantly related species growing in the same niche
4. Distantly related species growing in different habitats.

Answer: 1. Closely related species growing in the same niche

Question 42. Given below is an imaginary pyramid of numbers. What could be one of the possibilities about certain organisms at some of the different levels?

1. Level PC is “insects” and level SC is “small insectivorous birds”
2. Level PP is “phytoplanktons” in sea and “Whale” on top-level TC
3. Level one PP is “pipal trees” and the level SC is “sheep”
4. Level PC is “rats” and level SC is “cats”.

Answer: 1. Level PC is “insects” and level SC is “small insectivorous birds”

Question 43. Which of the following relations is correct regarding the GPP and NPP of an ecosystem?

1. NPP = GPP – Animal consumption
2. NPP = GPP + Plant respiration
3. NPP = GPP – Plant respiration
4. NPP = GPP + Animal consumption.

Answer: 3. NPP = GPP – Plant respiration

Question 44. An ecosystem resists change because it is in a state of:

1. Imbalance
2. Shortage of components
3. Homeostasis
4. Deficiency of light

Answer: 3. Homeostasis

Question 45. The ecosystem has two components:

1. Plants and animals
2. Weeds and trees
3. Biotic and abiotic
4. Frogs and men.

Answer: 3. Biotic and abiotic

Question 46. The number of producers within a specified area would be maximum in:

1. Pond ecosystem
2. Grassland
3. Desert
4. Forest ecosystem.

Answer: 1. Pond ecosystem

Question 47. In an ecosystem, a big fish eats small fishes which eat water fleas supported by phytoplanktons. The water fleas in this ecosystem are:

1. Producers
2. Primary consumers
3. Secondary consumer
4. Top consumers.

Answer: 2. Primary consumers

Question 48. Which one of the following represents the largest population in an ecosystem?

1. Consumers
2. Top consumers
3. Decomposers
4. Producers.

Answer: 4. Producers.

Question 49. With regard to the ecological food chain, man is a:

1. Consumer
2. Producer
3. Producer and consumer
4. Producer and decomposer.

Answer: 1. Consumer

Neet Previous Year Questions On Ecosystem

Question 50. The first link in a food chain is always a green plant because:

1. It has the capacity to synthesize organic food
2. Plants are fixed to a place
3. Plants are present everywhere
4. There are more herbivorous animals than carnivorous animals.

Answer: 1. It has the capacity to synthesize organic food

Question 51. A food chain is represented by :

1. Producers
2. Decomposers in succession
3. Primary consumers
4. Producers—consumers—decomposers.

Answer: 4. Producers—consumers—decomposers.

Question 52. Organisms linked in a food chain represent:

1. Food web
2. Trophic levels
3. Ecosystem
4. Community.

Answer: 2. Trophic levels

Question 53. Free-floating organisms are termed:

1. Planktons
2. Benthos
3. Nekton
4. All algae.

Answer: 1. Planktons

Question 54. The bottom-dwelling organisms are:

1. Nektons
2. Phytoplankton
3. Benthos
4. Zooplanktons.

Answer: 3. Benthos

Question 55. The first trophic level is represented by :

1. Herbivores
2. Carnivores
3. Insectivores
4. Autotrophs.

Answer: 4. Autotrophs

Question 56. In a grassland, top consumers are:

1. Herbivores
2. Carnivores
3. Bacteria
4. Tall pine tree.

Answer: 2. Carnivores

Question 57. The food chain in which micro-organisms absorb and break the energy-rich compounds synthesized by the producers is

1. Predator food chain
2. Parasitic food chain
3. Detritus food chain
4. None of the above.

Answer: 3. Detritus food chain

Question 58. Lichens do not normally grow in cities :

1. Because of the absence of the right type of algae and fungi
2. Because of the lack of moisture
3. Because of air pollution
4. Because natural habitat is missing.

Answer: 3. Because of air pollution

Question 59. Primary productivity of the ecosystem refers to:

1. Increase in primary consumers
2. Net production of primary producers
3. CO₂ fixation of organic carbon
4. Increase in mortality of primary producers.

Answer: 3. CO₂ fixation of organic carbon

Question 60. The individuals in the uppermost ring of the pyramid represent the one with:

1. Maximum number
2. Maximum biomass
3. The ultimate consumer in the chain
4. Minimum biomass.

Answer: 3. The ultimate consumer in the chain

Neet Previous Year Questions On Ecosystem

Question 61. The pyramid of a number of individuals per unit area in a grassland ecosystem will be:

1. Linear
2. Upright
3. Irregular
4. Inverted.

Answer: 2. Upright

Question 62. The ecological niche is:

1. Place of dwelling
2. Place of origin
3. Competitive ability
4. Function with habitat.

Answer: 4. Function with habitat.

Question 63. Which of the following food chains is correct?

1. Fallen leaves-bacteria-insect larvae
2. Phytoplankton -zooplankton-fish
3. Grasses-fox-rabbit
4. Grasses-chameleon -insect-bird.

Answer: 2. Phytoplankton -zooplankton-fish

Question 64. ‘Greenhouse effect’ is:

1. Growing maximum green plants in home gardens
2. Reduction of the green part of sunlight reaching the earth
3. Growing vegetables in green-coloured houses
4. Retention of heat radiation from the earth by CO₂

Answer: 4. Retention of heat radiation from the earth by CO₂

Question 65. For recycling of materials which one is necessary?

1. Producers
2. Consumer
3. Man
4. Decomposers.

Answer: 4. Decomposers

Question 66. Energy flow in an ecosystem is:

1. Multidirectional
2. Bidirectional
3. Unidirectional
4. None of the above.

Answer: 3. Unidirectional

Question 67. The pyramid of energy in a terrestrial ecosystem may be:

1. Inverted
2. Upright
3. Upright and inverted
4. None of the above.

Answer: 2. Upright

Ecosystem NEET Notes

Question 68. Green plants are:

1. Complete food chain
2. First trophic level
3. Second trophic level
4. Third trophic level.

Answer: 2. First trophic level

Question 69. Solar energy can be trapped to the maximum capacity by:

1. Planting trees
2. Crops
3. Grasses
4. Xerophytic plants.

Answer: 3. Grasses

Question 70. The equilibrium of species is disturbed by

1. Overgrazing
2. Selective grazing
3. Fanning
4. None of the above.

Answer: 1. Overgrazing

Question 71. A food chain starts with:

1. Decay
2. Photosynthesis
3. Respiration
4. Nitrogen fixation.

Answer: 2. Photosynthesis

Question 72. Biological equilibrium is an equilibrium among the:

1. Producers
2. Producers and consumers
3. Decomposers
4. Producers, consumers, and decomposers.

Answer: 4. Producers, consumers, and decomposers.

Question 73. When the number of organisms at successive levels are plotted, they assume the shape of a pyramid. This is called:

1. Pyramid of Numbers
2. Pyramid of Energy
3. Pyramid of Biomass
4. None of these.

Answer: 1. Pyramid of Numbers

Question 74. The salt concentration in the open sea is about:

1. 35 per cent
2. 3.5 per cent
3. 85 per cent
4. 0.8 per cent.

Answer: 2. 3.5 per cent

Question 75. The upper vertical zone up to the depth of 200 meters is known as:

1. Photic zone
2. Aphotic zone
3. Abyssal zone
4. None of these.

Answer: 1. Photic zone

Question 76. In a food chain, the largest number is of:

1. Decomposers
2. Consumers
3. Predators
4. Producers.

Answer: 4. Producers.

Question 77. The ecosystem is a self-sustaining unit because it consists of:

1. Plants and animals only
2. Physical environment only
3. Microbes only
4. All the above.

Answer: 4. All the above.

Question 78. A component of the physical environment of an ecosystem is:

1. Sunlight
2. Decomposers
3. Water
4. Temperature.

Answer: 1. Sunlight

Question 79. In a food chain animals constitute the:

1. First trophic level
2. Second trophic level
3. Intermediate trophic level
4. Ultimate trophic level.

Answer: 3. Intermediate trophic level

Ecosystem NEET Notes

Question 80. Second-order consumers are:

1. All heterotrophs
2. Animals feeding on plants
3. Animals preying on herbivorous animals
4. Larger animals.

Answer: 3. Animals preying on herbivorous animals

Question 81. Active swimmers are:

1. Phytoplankton
2. Nektons
3. Benthos
4. Zooplankton.

Answer: 2. Nektons

Question 82. A food web is constituted by:

1. Various interlinked food chains in a community
2. Relationship between organisms and their environment
3. Relationship between plants and animals
4. Relationship between plants, animals and microbes.

Answer: 1. Various interlinked food chains in a community

Question 83. Vegetation found around the Mediterranean coast is called:

1. Savannah
2. Prairie
3. Chaparral
4. Melee.

Answer: 3. Chaparral

Question 84. An ecosystem is a complex interacting system of:

1. Individuals
2. Population
3. Communities and their physical environment
4. Communities and their soil condition.

Answer: 3. Communities and their physical environment

Question 85. Which of the following is truly a biome?

1. Wheat crop field
2. Pond ecosystem
3. Greenfield
4. Deciduous forest.

Answer: 4. Deciduous forest.

Question 86. The ecological niche of an organism is its:

1. Way of life
2. Habitat
3. Habitat as well as climate
4. Defended territory.

Answer: 1. Way of life

Question 87. Which of the following forests is more diverse?

1. Coniferous evergreen
2. Deciduous evergreen
3. Tropical rain forest
4. Sub-tropical rain forest.

Answer: 3. Tropical rainforest

Question 88. The solar energy is trapped to the maximum by:

1. Wheat
2. Rice
3. Sugarcane
4. Grams.

Answer: 1. Wheat

Question 89. Agroecosystem is a:

1. Natural ecosystem
2. Man-made ecosystem
3. Balanced ecosystem
4. Peripheral ecosystem.

Answer: 2. Man-made ecosystem

Question 90. Mangrove vegetation is found in:

1. Dehradun valley
2. Kulu valley
3. Western ghats
4. Sunderbans.

Answer: 4. Sunderbans.

Question 91. In a grassland ecosystem, the pyramid of energy is as:

1. Inverted
2. Upright
3. Inverted or upright
4. None of the above.

Answer: 2. Upright

Question 92. Which of the following is one-way flow rather than two directions or cyclic?

1. Nitrogen
2. Potassium
3. Free energy
4. Both (2) and (3).

Answer: 4. Both (2) and (3).

Question 93. The photic zone is spread up to a depth of:

1. 10 m
2. 10-100m
3. 100-300 m
4. 200 m.

Answer: 4. 200 m.

Question 94. Chaparral occurs in the Mediterranean area and rainfall occurs during:

1. Throughout the year
2. Summer
3. Winter
4. Spring.

Answer: 3. Winter

Neet Biology Ecosystem Notes Pdf

Question 95. The most diverse oceanic communities are in the:

1. Abyssal zone
2. Littoral zone
3. Neritic zone
4. Oceanic zone.

Answer: 2. Littoral zone

Question 96. Daily tidal cycle recurs after:

1. 8 hrs
2. 12.4 hrs
3. 10.4 hrs
4. 12 hrs

Answer: 2. 12.4 hrs

Question 97. The pyramid of numbers is based on

1. Unit per area
2. Food per individual
3. Individuals with trophic levels
4. None of the above.

Answer: 3. Individuals in trophic levels

Question 98. Bach couple should produce only two children which will help in

1. Checking pollution
2. Stabilizing the ecosystem
3. Fertility of soil
4. Improving food web.

Answer: 2. Stabilising the ecosystem

Question 99. The trophic level of Woji in a forest ecosystem is:

1. T₃
2. T₄
3. T₂
4. T₁

Answer: 2. T₄

Question 100. About how much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

1. 10%
2. 1%
3. 30%
4. 50%.

Answer: 1. 10%

Question 101. About how much of the net primary productivity of an aquatic ecosystem is eaten and digested by herbivores?

1. 1%
2. 10%
3. 40%
4. 90%.

Answer: 4. 90%

Question 102. Life without air is:

1. Free from oxidative damage
2. Impossible
3. Anaerobic
4. Reduction in life spam

Answer: 3. Anaerobic

Question 103. Tropical dense forest is due to:

1. High temp, and excess rain
2. Low temp, and excess rain
3. High temp, and less rain
4. Wild animals like tigers, lions, bears.

Answer: 1. High temp, and excess rain

Question 104. The pyramid of energy is always:

1. Inverted
2. Upright
3. Both upright and inverted
4. Inverted in the forest ecosystem.

Answer: 2. Upright

Question 105. A kite eats mice, mice live on grains, Hence the kite is a:

1. Primary producer
2. Secondary consumer
3. Primary consumer
4. Secondary producer.

Answer: 2. Secondary consumer

Question 106. The composition of soil air is affected by:

1. Pore size
2. Soil organisms
3. Type of roots
4. All of these.

Answer: 4. All of these

Components Of Ecosystem NEET Biology

Question 107. Plants growing in alpine zone are short due to:

1. Low temperature
2. High wind velocity
3. High light intensity
4. None of these.

Answer: 2. High wind velocity

Question 108. Plants growing in the seashore are generally resistant to:

1. Lodging
2. Erosion
3. Salt spray
4. Injuries.

Answer: 3. Salt spray

Question 109. An anatomical feature that exclusively develops to counter the high velocity of wind:

1. Reaction wood formation
2. Absence of secondary growth
3. Absence of leaves
4. Absence of more branches.

Answer: 1. Reaction wood formation

Question 110. The classification of plant groups on the basis of temperature differentiating four zones such as mega therms was proposed by:

1. Clements
2. Raunkiaer
3. Odum
4. Warming.

Answer: 2. Raunkiaer

Question 111. Flowering is induced if germinating seeds are exposed

1. Low temperature
2. High temperature
3. Temperature below freezing
4. Temperature above 45°C.

Answer: 1. Low temperature

Question 112. The percentage of light from total solar input utilized by plants:

1. About 1 %
2. 3-5%
3. 7-8%
4. 14%.

Answer: 1. About 1 %

Question 113. Albido value refers to:

1. Turbidity of solar radiations
2. Percentage of solar absorption
3. Percentage of reflected light by a surface
4. Amount of light absorbed by forests.

Answer: 3. Percentage of reflected light by a surface

Question 114. According to Geiger, the percentage of light reflected by the clouds is

1. 9%
2. 10%
3. 48%
4. 33%.

Answer: 4. 33%.

Question 115. The albedo value of a forest is around:

1. 1-2%
2. 3-5%
3. 5-10%
4. 20-30%.

Answer: 3. 5-10%

Question 116. The aquatic thermal strata where no temperature gradients are observed is called as:

1. Hypolimnion
2. Metalimnion
3. Epilimnion
4. Thermocline.

Answer: 1. Hypolimnion

Neet Biology Ecosystem Notes Pdf

Question 117. The alpine forests are classed under the plant group called:

1. Mesotherms
2. Hekistotherms
3. Microtherms
4. Megatherms.

Answer: 2. Hekistotherms

Question 118. The optimum temperature for seedling growth in the upper Gangetic plains is around:

1. 10°-15°C
2. 5°-10°C
3. 0°-25°C
4. 30°—40°C.

Answer: 3. 0°-25°C

Question 119. When a plant of ho^ climate is transferred to colder regions, it gets an injury called:

1. Chilling
2. Thermal death
3. Desiccation
4. Freezing.

Answer: 1. Chilling

Question 120. In the western Himalayas, the Betula trees usually occur in:

1. Tropical zone
2. Sub-tropical zone
3. Alpine zone
4. Temperate zone.

Answer: 3. Alpine zone

Question 121. Annual carbon fixation by photosynthesis is:

1. 7 x 10¹³
2. 7×10¹⁰
3. 7 x 10¹²
4. 7 x 10²⁰

Answer: 1. 7 x 10¹³

Question 122. Annual world precipitation is:

1. 7 x 10¹⁰ g
2. 7 x 10¹⁰ g
3. 4.46 x 10¹⁰ g
4. 4.46 x 10²⁰ g.

Answer: 4. 4.46 x 10²⁰ g.

Question 123. Maximum oxygen comes from:

1. Phytoplankton
2. Grasslands
3. Forests
4. Herbs and shrubs.

Answer: 1. Phytoplankton

Question 124. The main nitrogen reservoir in the biosphere is:

1. Atmosphere
2. Ocean
3. Organisms
4. Rocks.

Answer: 1. Atmosphere

Ecosystem Notes For Neet

Question 125. Which one of the following pairs is a sedimentary type of biogeochemical cycle?

1. Phosphorus and CO₂
2. Oxygen and Nitrogen
3. Phosphorus and Nitrogen
4. Phosphorus and Sulphur.

Answer: 4. Phosphorus and Sulphur

Question 126. The largest reservoir of phosphorus in the biosphere is the

1. Atmosphere
2. Ocean
3. Organisms
4. Rocks.

Answer: 4. Rocks

Question 127. Which one of the following pairs is a sedimentary type of biogeochemical cycle?

1. Phosphorus and CO₂
2. Oxygen and Nitrogen
3. Phosphorus and Nitrogen
4. Phosphorus and Sulphur.

Answer: 4. Phosphorus and Sulphur

Question 128. Sedge is:

1. Polygonum
2. Potamogeton
3. Carex
4. Typha.

Answer: 3. Carex

Question 129. The perennial grass stage is represented by:

1. Aristida
2. Heteropogon
3. Poa
4. Tortula.

Answer: 2. Heteropogon

Question 130. The series of changes on the previously barren area is:

1. Sere
2. Climax community
3. Primary succession
4. Secondary succession.

Answer: 3. Primary succession

Question 131. Crustose lichen is:

1. Rhizocarpon
2. Pannelia
3. Dermatocarpon
4. Cladonia.

Answer: 3. Dermatocarpon

Ecosystem Notes For Neet

Question 132. Secondary succession will not be completed if the bare area is invaded by:

1. Sphagnum
2. Lantana
3. Eichhomia
4. All the above.

Answer: 4. All the above

Question 133. Plant succession occurring in a sandy area is:

1. Psammosere
2. Halosere
3. Xerosere
4. Hydrosere.

Answer: 1. Psammosere

Question 134. A plant growing on rock is:

1. Psammophyte
2. Eremophyte
3. Lithophyte
4. Chersophyte.

Answer: 3. Lithophyte

NEET Biology Ecosystem Questions From Competitive Examinations

Question 1. Green plants constitute:

1. First trophic level
2. Second trophic level
3. Third trophic level
4. Fourth trophic level.

Answer: 1. First trophic level

Question 2. Tip of an ecological pyramid is occupied by:

1. Producers
2. Herbivores
3. Carnivores
4. None of the above.

Answer: 3. Carnivores

Question 3. Zooplanktonic forms are:

1. Primary producers
2. Carnivores
3. Primary consumers
4. Secondary consumers.

Answer: 3. Primary consumers

Question 4. Which of the following occurs in the abiotic component of the ecosystem?

1. Flow of energy
2. Cycling of materials
3. Consumers
4. Flow of energy and cycling of materials.

Answer: 2. Cycling of materials

Question 5. A treeless biome is:

1. Tundra
2. Grassland
3. Desert
4. All the above.

Answer: 4. All the above

Question 6. A man-made micro-ecosystem is:

1. Plants grown in a pond
2. Crop field
3. Tank formed naturally in your courtyard
4. Lake in a forest.

Answer: 2. Crop field

Energy Flow In Ecosystem NEET Study Material

Question 7. Which one has always a steeper vertical gradient?

1. Pyramid of mass
2. Pyramid of energy
3. Pyramid of numbers
4. Pyramid of energy in aquatic ecosystem.

Answer: 2. Pyramid of energy

Question 8. Which one is exclusive of xerophytic adaptation?

1. Absence of stomata
2. Long tap root system
3. Stipular leaves
4. Spines.

Answer: 4. Spines.

Question 9. Which one has evergreen vegetation and drought-adapted animals?

1. Chaparral
2. Savannah
3. Tundra
4. Deciduous forest.

Answer: 1. Chaparral

Question 10. Which part of the world has a high density of organisms?

1. Grasslands
2. Savannahs
3. Deciduous forests
4. Tropical rain forests.

Answer: 4. Tropical rainforests

Question 11. Viviparity and pneumatophores are features of:

1. Hydrophytes
2. Halophytes
3. Mesophytes
4. Xerophytes.

Answer: 2. Halophytes

Question 12. The flora and fauna in lakes or ponds are:

1. Lefitic biota
2. Lotic biota
3. Abiotic biota
4. Field layer.

Answer: 1. Lefitic biota

Components Of Ecosystem NEET Biology

Question 13. Trophic levels are formed by:

1. Only plants
2. Only animals
3. Only carnivores
4. Organisms linked in food chains.

Answer: 4. Organisms linked in food chains.

Question 14. An ecosystem has which of the following two components?

1. Frogs and men
2. Weeds and trees
3. Biotic and abiotic
4. Plants and animals.

Answer: 3. Biotic and abiotic

Question 15. The atmospheric/humidity is measured by

1. Potometer
2. Photometer
3. Hygrometer
4. Auxanometer.

Answer: 3. Hygrometer

Question 16. The concept of ecological pyramids was developed by

1. Elton
2. Darwin
3. Odum
4. Reiter.

Answer: 1. Elton

Question 17. Feeding on herbivorous insects is:

1. Primary consumer
2. Secondary consumer
3. Tertiary consumer
4. Top carnivore.

Answer: 2. Secondary consumer

Question 18. Maximum biomass of autotrophs in oceans is made of:

1. Benthic brown algae, coastal red algae, and daphnids
2. Benthic diatoms and marine viruses
3. Seagrasses and slime molds
4. Free-floating microalgae, cyanobacteria, and nanoplankton.

Answer: 4. Free-floating microalgae, cyanobacteria, and nanoplankton.

Question 19. Terai forest is:

1. Tropical
2. Coniferous
3. Deciduous
4. Temperate deciduous.

Answer: 1. Tropical

Ecosystem Notes For Neet

Question 20. Savannah is found commonly in :

1. U.S.A.
2. U.S.S.R.
3. Australia
4. India.

Answer: 3. Australia

Question 21. A recently discovered ecosystem is:

1. Crater
2. Tundra
3. Floating Iceberg
4. Vent.

Answer: 1. Crater

Question 22. Controlling factors in the ecosystem is:

1. Soil moisture
2. Food
3. Trepidation
4. Temperature.

Answer: 3. Trepidation

Question 23. The transition zone between the two vegetational types is:

1. Ecotone
2. Ecotype
3. Ecocline
4. Ecosystem.

Answer: 1. Ecotone

Question 24. Plant decomposers are:

1. Monera and fungi
2. Fungi and plants
3. Protista and Animalia
4. Animalia and Monga.

Answer: 1. Monera and fungi

Question 25. The ecosystem consists of:

1. Producers
2. Consumers
3. Decomposers
4. All of these.

Answer: 4. All of these.

Question 26. Desert can be converted into green land by planting:

1. Oxylophytes
2. Psammophytes
3. Halophytes
4. Tropical trees.

Answer: 2. Psammophytes

Question 27. In the food chain, the lion is a:

1. Primary consumer
2. Secondary producer
3. Tertiary consumer
4. Secondary consumer.

Answer: 3. Tertiary consumer

Question 28. Which ecosystem shows maximum genetic diversity?

1. Tropical rain forests
2. Temperate forests
3. Coniferous forests
4. Subtropical forests.

Answer: 1. Tropical rainforests

Question 29. Which of the following is correctly matched?

1. Butterfly camouflage
2. Garden lizard mimicry
3. House lizard autotomy
4. None of these.

Answer: 3. House lizard autotomy

Nutrient Cycling In Ecosystems NEET

Question 30. Organisms found at the bottom of the sea are:

1. Planktons
2. Benthos
3. Nektons
4. Phytons.

Answer: 2. Benthos

Question 31. X is eating curd/yogurt. For this food intake in a food chain, he should be considered as occupying:

1. First trophic level
2. Second trophic level
3. Third trophic level
4. Fourth trophic level.

Answer: 3. Third trophic level

Question 32. These belong to the category of primary consumers:

1. Eagle and snake
2. Insects and cattle
3. Snake and Frog
4. Water insects.

Answer: 2. Insects and cattle

Question 33. If the high-altitude birds become rare or extinct, the plants that may disappear along with them are:

1. Pine
2. Oak
3. Orchids
4. Rhododendrons.

Answer: 2. Oak

Question 34. An ecosystem that can be easily damaged but can recover after some time if the damaging effect stops will have the following:

1. Low stability and low resilience
2. High stability and high resilience
3. Low stability and high resilience
4. High stability and low resilience.

Answer: 3. Low stability and high resilience

Question 35. Which of the following is expected to have the highest value (gm/m²/year) in a grassland ecosystem?

1. Gross production (GP)
2. Net production (NP)
3. Secondary production
4. Tertiary production.

Answer: 1. Gross production (GP)

Question 36. If by radiation all nitrogenase enzymes are inactivated, then there will be no:

1. Conversion from nitrate to nitrite in the legumes
2. Conversion from ammonium to nitrate in soil
3. Fixation of nitrogen in the legumes
4. Fixation of atmospheric nitrogen.

Answer: 4. Fixation of atmospheric nitrogen.

Question 37. The Great Barrier Reef along the east coast of Australia can be categorized as:

1. Population
2. Community
3. Ecosystem
4. Biome.

Answer: 4. Biome.

Question 38. Which one of the following pairs is mismatched?

1. Savannah – acacia trees
2. Prairie – epiphytes
3. Tundra – permafrost
4. Coniferous forest – evergreen trees.

Answer: 2. Prairie – epiphytes

Question 39. Which one of the following is the correct matching of the plant, its habitat, and the forest type where it normally occurs?

1. Prosopis, tree, scrub
2. Saccharum, grass, forest
3. Shorea robusta, herb, tropical rainforest
4. Acacia catechu, tree, coniferous forest.

Answer: 2. Saccharum, grass, forest

Question 40. Given below is one of the types of ecological pyramids. This type represents:

1. Pyramid of numbers in a grassland
2. Pyramid of biomass in a fallow land
3. Pyramid of biomass in a lake
4. Energy pyramid in a spring.

Answer: 3. Pyramid of biomass in a lake

Question 41. Energy transferred from one trophic level to another is:

1. 5%
2. 10%
3. 15%
4. 20%.

Answer: 2. 10%

Question 42. Maximum absorption of rainfall water is done by:

1. Tropical deciduous forest
2. Tropical evergreen forest
3. Tropical savannah
4. Scrub forest.

Answer: 2. Tropical evergreen forest

Question 43. The pyramid of energy is always upright for any ecosystem. This situation indicates the fact that

1. Producers have the lowest energy conversion efficiency
2. Carnivores have a better energy conversion efficiency
3. Energy conversion efficiency is the same in all trophic levels
4. Herbivores have a better energy conversion efficiency than carnivores.

Answer: 4. Herbivores have a better energy conversion efficiency than carnivores.

Question 44. Which of the following is called as a detritivore?

1. An animal feeding on decaying organic matter
2. An animal feeding on a plant
3. A plant feeding on an animal
4. An animal feeding on another animal.

Answer: 1. An animal feeding on decaying organic matter

Question 45. Which one of the following is not used for the construction of ecological pyramids?

1. Dry weight
2. Fresh weight
3. Rate of energy flow
4. Number of individuals.

Answer: 2. Fresh weight

Nutrient Cycling In Ecosystems NEET

Question 46. In the given formula, what does “a” represent?

Formula: Assimilatory efficiency = \(\frac{\text{Use of energy in food}{“a”}}\) x 100.

1. Energy obtained through primary producer
2. Biomass at own level
3. Biomass at lower trophic level
4. Energy is obtained through food.

Answer: 4. Energy obtained through food.

Question 47. Increased asthmatic attacks in certain seasons are related to:

1. Eating fruits preserved in tin containers
2. Inhalation of seasonal pollen
3. Low temperature
4. Hot and humid environment.

Answer: 2. Inhalation of seasonal pollen

Question 48. Which one of the following ecosystem types has the highest annual net primary productivity?

1. Tropical deciduous forest
2. Temperate evergreen forest
3. Temperate deciduous forest
4. Tropical rain forest.

Answer: 4. Tropical rainforest.

Question 49. Identify which one of the following is an example of an incomplete ecosystem.

1. Cave
2. Grassland
3. River
4. Wetland.

Answer: 1. Cave

Question 50. Consider the following statements concerning food chains.

1. Removal of 80% of tigers from an area resulted in greatly increased growth of vegetation
2. Removal of most of the carnivores resulted in an increased population of deer
3. The length of food chains is generally limited to 3-4 trophic levels due to energy loss
4. The length of food chains may vary from 2 to 8 trophic levels.

Answer: 3. The length of food chains is generally limited to 3-4 trophic levels due to energy loss

Question 51. Large Woody Vines are more commonly found in:

1. Temperate forests
2. Mangroves
3. Tropical rainforests
4. Alpine forests.

Answer: 3. Tropical rainforests

Question 52. Which one of the following statements for the pyramid of energy is incorrect, whereas the remaining three are correct?

1. Its base is broad
2. It shows the energy content of different trophic-level organisms
3. It is inverted in shape
4. It is upright in shape.

Answer: 3. It is inverted in shape

Question 53. The mass of living matter at a trophic level in an area at any time is called:

1. Standing crop
2. Detritus
3. Humus
4. Standing state.

Answer: 4. Standing state.

Question 54. Of the total incident solar radiation, the proportion of PAR is:

1. About 70%
2. About 60%
3. Less than 50%
4. More than 50%.

Answer: 4. More than 50%.

Question 55. Identify the possible link, “A” in the following food chain:

Plan—insect—frog—‘ ‘A” —Eagle

1. Wolf
2. Cobra
3. Parrot
4. Rabbit.

Answer: 2. Wolf

Question 56. The upright pyramid of numbers is absent in:

1. Forest
2. Lake
3. Grassland
4. Rabbit.

Answer: 2. Lake

Question 57. An inverted pyramid of numbers and an inverted pyram of biomass are respectively seen in

1. Grassland and tree ecosystem
2. Sea and tree ecosystem
3. Tree and sea ecosystem
4. Sea and grassland ecosystem.
5. Tree and grassland ecosystem.

Answer: 3. Sea and grassland ecosystem

Question 58. Which of the following is a pioneer in xerarch success?

1. Phytoplanktons
2. Lichens
3. Bryophytes
4. Rooted hydrophytes
5. Sedges

Answer: 2. Lichens

Question 59. The natural reservoir of phosphorus is

1. Animal bones
2. Rock
3. Fossils
4. Sea water.

Answer: 2. Rock

Question 60. Which one of the following processes during decomposition is correctly described?

1. Humification leads to the accumulation of a dark coloured substance humus which undergoes microbial action at a very fast rate.
2. Catabolism-Last step decomposition under fully anaerobic condition
3. Leaching-Water soluble inorganic nutrients rise to the top layers of soil
4. Fragmentation- carried out by organisms such as earthworms.

Answer: 4. Fragmentation- carried out by organisms such as earthworms.

Question 61. Secondary productivity is the rate of formation of new organic matter by:

1. Parasite
2. Consumer
3. Decomposer
4. Producer.

Answer: 2. Consumer

NEET Biology Gymnosperms Multiple Choice Questions

Question 1. Which one of the features is true for Pinus

1. Pivsenee of antheridia
2. Double fertilization
3. Biciliated sperms
4. Haploid endosperm.

Answer: 4. Haploid endosperm.

Question 2. Needles of finns possess meristem at:

1. Apical portion
2. Intercalary portion
3. Basal portion
4. Lateral portion.

Answer: 3. Basal portion

Question 3. Pinewood consists almost entirely of:

1. Tracheids with bordered pits
2. Vessels
3. Tracheids and vessels both in equal amount
4. More vessels than tracheids.

Answer: 1. Tracheids with bordered pits

Question 4. In the embryo of pinus, rosette cells lie :

1. Above suspensor cells
2. Between suspensor and embryonal cells
3. Between primary and secondary suspensor cells
4. Between embryonal cells and apical cells.

Answer: 1. Above suspensor cells

Read and Learn More NEET Biology Multiple Choice Question and Answers

Question 5. The resin duct of a gymnospermous stem is an example of:

1. Intercellular space
2. Schizogenous cavity
3. Lysigenous cavity
4. Big vacuole.

Answer: 2. Schizogenous cavity

Question 6. The time required between formation in pinus is :

1. Three months
2. Six months
3. nine months
4. Twelve months.

Answer: 4. Twelve months.

NEET Biology Gymnosperms Questions

Question 7. The gametophytes of pinus are protected from desiccation by living in

1. Moist soil
2. Moist tissue of sporophyte in the cone
3. Bogs and marshes
4. The rainy season only.

Answer: 2. Moist tissue of sporophyte in the cone

Question 8. Which statement out of the following is correct regarding pinus?

1. Pinus forms deciduous trees in temperate regions
2. Pinus grows in deserts and exhibits xerophytic characters
3. Pinus is cosmopolitan in distribution
4. Pinus is of great economic value.

Answer: 4. Pinus is of great economic value.

Question 9. Which is the smallest gymnosperm among the following?

1. Cerberus
2. Dalbergia
3. Pinus
4. Guest

Answer: 3. Pinus

Question 10. In gymnosperms, archegonia lack :

1. Neck canal cells
2. Venter cells
3. Both
4. None of these.

Answer: 4. None of these.

Question 11. The megasporangium is also known as:

1. Fruit
2. Endosperm
3. Micropyle
4. Ovule.

Answer: 3. Micropyle

Question 12. Which one is common between funaria and pinus?

1. No fruits are produced
2. No seeds are produced
3. Anthcridia and archegonia are present
4. A pollen tube is formed.

Answer: 1. No fruits are produced

NEET Biology Gymnosperms Questions

Question 13. In pinus, the terminal portion of the ovuliferous scale is called :

1. Embryo sac
2. Bract scale
3. Ovule
4. Apophysis.

Answer: 4. Apophysis.

Question 14. Which of the following sets of structures in pinus belong entirely to the gametophytic generation?

1. Ovuliferous scale, embryo, bract scale
2. Bract scale, urothelial cells in pollen, integument
3. Embryo, endosperm, pollen
4. Endosperm, sperm, megaspore.

Answer: 4. Endosperm, sperm, megaspore.

Question 15. The edible part of the seed of the pinus :

1. Epispore
2. Endosperm
3. Perisperm
4. Pericarp.

Answer: 4. Pericarp.

Question 16. The group of phanerogams which have naked seeds or which produce ovules and seeds exposed on open sporophytes are called:

1. Phanerogams
2. Angiosperms
3. Gymnosperms
4. Spermatophyta.

Answer: 2. Angiosperms

Question 17. The roots of gymnosperm are:

1. Taproot
2. Adventitious roots
3. Rhizoid
4. Rhizophores.

Answer: 3. Rhizoid

NEET Biology Gymnosperms Questions

Question 18. In which of the following manners do gymnosperms differ from angiosperms?

1. Formation of endosperm before fertilization
2. Formation of pollen tube
3. Production of ovules
4. None of the above.

Answer: 1. Formation of endosperm before fertilization

Question 19. Angiosperms and gymnosperms resemble in having:

1. Vessels in wood
2. Mode of fertilization
3. Siphonogamy
4. Nature of endosperm.

Answer: 1. Vessels in wood

Question 20. The nucellus in a gymnosperm has 24 chromosomes, the number of chromosomes in its endosperm cells will be:

1. 48
2. 36
3. 24
4. 12.

Answer: 3. 24

Question 21. Microsporophyll of pinus is equivalent to :

1. Pollen grain of angiosperms
2. Stamen
3. Male gamelophyte
4. Inflorescence.

Answer: 4. Inflorescence.

Question 22. Transfusion tissue replaces the veins in:

1. Cycas
2. Ferns
3. Pinus and years
4. Selaginella.

Answer: 2. Ferns

Question 24. The giant tree among the pines belongs to the genus:

1. Cedrus
2. Pinus
3. Calbcrgia
4. Sequoia.

Answer: 4. Sequoia.

Gymnosperms and Angiosperms MCQs NEET

Question 25. Canada balsam is an oleoresin obtained from:

1. Abies balsamea
2. Impatiens balsamic
3. Finns
4. Helianthus

Answer: 1. Abies balsamea

Question 26. Plant of pine is:

1. Annual herb
2. Biennial herb
3. Evergreen tree
4. Deciduous tree.

Answer: 3. Evergreen tree

Question 27. The megasporophyll of pinus consists of :

1. Both bract and ovuliferous scales
2. Only bract scales
3. Only ovuliferous scales
4. None of the above.

Answer: 1. Both bract and ovuliferous scales

Question 28. The neck of the archegonium in pinus:

1. Five tiers of cells
2. Six to eight tiers of 4 cells
3. Two tiers of 4 cells
4. None of the above.

Answer: 3. Two tiers of 4 cells

Question 29. The seed of pinus is:

1. A monocotyledonous
2. Dicotyledonous
3. Polycotyledonous
4. Tetracotyledonous.

Answer: 3. Polycotyledonous

Question 30. The wing of the seed of pinus develops from ;

1. The outer layer of the integument and basal part of the ovuliferous scale
2. The inner layer of the integument and basal part of the ovuliferous scale
3. Only from the outer layer of the integument
4. From ovuliferous scale.

Answer: 4. Frorn ovuliferous scale.

Question 31. In pinus, female gametophyte develops only from :

1. Uppermost haploid megaspore
2. The lowermost haploid megaspore
3. Penultimate megaspore
4. The megaspore.

Answer: 2. The lowermost haploid megaspore

Gymnosperms and Angiosperms MCQs NEET

Question 32. The foliage leaves or needles irc pinus are borne by:

1. Branches of unlimited growth
2. Branches of limited growth
3. Branches of limited and unlimited growth
4. Female cones.

Answer: 2. Branches of limited growth

Question 33. What nature does, the acicular nature of the pinus needle depict?

1. Mesophytic
2. Xerophytic
3. Xerophytic
4. Sporophytic.

Answer: 2. Xerophytic

Question 34. Female gametophyte (endosperm) in pinus is formed :

1. Before fertilization
2. After pollination
3. After fertilization
4. None of the above,

Answer: 1. Before fertilization

Question 36. Gymnosperms originated in:

1. Cenozoic
2. Palaeozoic
3. Precambrian
4. Mesozoic.

Answer: 2. Palaeozoic

Question 37. Gymnosperms differ from angiosperms in :

1. Having seeds
2. Having naked ovules
3. Showing heterospory
4. None of the above.

Answer: 2. Having naked ovules

Gymnosperms and Angiosperms MCQs NEET

Question 38. Turpentine is obtained from:

1. Curcuma longa
2. Bryophyte
3. Pinus australis
4. Ophioglossum.

Answer: 3. Pinus australis

Question 39. In pinus only the lower part of the oospore is concerned with the development of the embryo, such development is :

1. Periblastic
2. Holoblastic
3. Meroblastic
4. None of these.

Answer: 3. Meroblastic

Question 40. The mature embryo of the pinus consists of :

1. Radicle and plumule
2. 1 + 10 Cotyledons
3. Radicle, plumule and many cotyledons
4. 3 + Endosperm.

Answer: 3. Radicle, plumule and many cotyledons

Question 41. The wood obtained from the pinus plant is used for:

1. Furniture
2. Building purposes
3. Matchboxes
4. All the above.

Answer: 4. All the above.

Question 42. Winged seeds are found in :

1. Cycas
2. Pinus
3. Papaver species
4. None of the above.

Answer: 2. Pinus

Gymnosperms and Angiosperms MCQs NEET

Question 43. Integument in pinus ovule is :

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

Answer: 2. Diploid

Question 44. Sclerenchyma of the hypodermis of the pinus needle helps in:

1. Photosynthesis
2. Increasing absorption
3. Providing support
4. Checking transpiration,

Answer: 3. Providing support

Question 45. Perisperm is :

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

Answer: 2. Diploid

Question 46. The number of archegonia in the pinus ovule is generally

1. 1 To 4
2. 2 To 5
3. 2 To 6
4. 1 To 8.

Answer: 2. 2 To 5

NEET Previous Year Questions on Gymnosperms

Question 47. Ovules in the pinus are generally:

1. Anatropous with three integuments
2. Anatropous with one integument
3. Amphitropous with three integuments
4. Orthotropous with one integument.

Answer: 2. Anatropous with one integument

NEET Biology Plant Kingdom Questions Question 48. In pinus, megaspores on germination forms :

1. Pollen tube with two motile sperms
2. Endosperm with archegonia
3. Endosperm with sperms
4. Endosperm with embryo core.

Answer: 2. Endosperm with archegonia

Question 49. Among the following which docs do not belong to sporophyte generation in pinus?

1. Roots
2. Endosperm
3. Dwarf shoot
4. Long shoot.

Answer: 2. Endosperm

Question 50. In pinus sylvestris spur is:

1. Trifoliar
2. Bifoliar
3. Multifoliar
4. Tetrafoliar.

Answer: 2. Bifoliar

Question 51. Chailgoza is obtained from:

1. Pinus roxburghii
2. Pinus gerardiana
3. Pinus wallichiana
4. Pinus longifolia

Answer: 2. Pinus gerardiana

NEET Previous Year Questions on Gymnosperms

Question 52. The girdle loaf traces in Cyrus go to leaves :

1. After making a semi-circle
2. After making a complete circle
3. After making two concentric circles
4. None of the above.

Answer: 1. After making a semi-circle

Question 53. The male cone of the pinus is a modification of

1. Simple polyembryony
2. Cleavage polyembryony
3. Both simple and cleavage polyembryony
4. None of the above.

Answer: 2. Cleavage polyembryony

NEET Biology Plant Kingdom Questions Question 54. The female cone of the pinus is a modification of

1. Branches
2. Dwarf shoot
3. Long shoot
4. Leaf

Answer: 3. Long shoot

Conifers And Cycads MCQs For NEET

Question 55. In cycas, megasporangia are located on its megasporophyll

1. Dorsally
2. Ventrally
3. Laterally
4. Apically

Answer: 3. Laterally

Question 57. Seed of finns shows three generations as :

1. Parent sporophyte, gametophyte and future sporophyte
2. Parent gametophyte, sporophyte and future gametophyte
3. Parent sporophyte, sporophyte, future gametophyte
4. All three sporophytes.

Answer: 1. Parent sporophyte, gametophyte, and future sporophyte

Question 58. Finns seed shows:

1. Hypogeal germination
2. Epigeal germination
3. Dormancy
4. None of the above

Answer: 2. Epigeal germination

Question 59. Monkey puzzle is common name of:

1. Araucaria auracana
2. Finns raxburghii
3. Taxodium
4. Cedrus deodora.

Answer: 1. Araucaria auracana

Question 60. The female cone of the pinus can be compared to which part of the plant:

1. Flower
2. Mcgasporophyll
3. Inflorescence
4. Microsporophyll.

Answer: 3. Inflorescence

Question 61. Female cone of finns forms seed in:

1. One year
2. Two years
3. Three years
4. Four years.

Answer: 3. Three years

Question 62. The male gametophyte of cycas differs from that of an angiosperm in:

1. Producing two male gametes
2. Producing a pollen tube with a tube nucleus and two ciliated motile male gametes
3. Producing a pollen tube and a nucleus
4. Starting its formation in situ.
5. Answer: 2. Producing a pollen tube with a tube nucleus and two ciliated motile male gametes

Question 63. In which portion of Cyrus are found diplomatic vascular bundles?

1. Root
2. Stem
3. Leaflet
4. Racltis and leaflet.

Answer: 4. Racltis and leaflet.

NEET Botany Important Questions On Gymnosperms

Question 64. In which of the following regions of cyras the algal zone is found?

1. Stem
2. Normal roots
3. Coralloid roots
4. Leaflet.

Answer: 3. Coralloid roots

Question 65. Male cone of pinus replaces:

1. Ncedlcs
2. Scales
3. Dwarf shoots
4. Long shoots.

Answer: 3. Dwarf shoots

Question 66. Pollen grains in cycas arc shed at:

1. 1-Celled stage
2. 2-Celled stage
3. 3-Celled stage
4. 4-Cellcd stage.

Answer: 3. 3-Cellcd stage

Question 67. In cycas, the pollen lube is:

1. Haustorial in nature
2. Sperm carrier
3. Carrier of ovule
4. Carrier of archegonia.

Answer: 2. Sperm carrier

Question 68. Pinus is:

1. Deciduous
2. Dioecious
3. Monoecious
4. None of these.

Answer: 3. Monoecious

Question 69. Antherozoids of cycas are :

1. Aflagellate
2. Dinoflagellate
3. Triflagellale
4. Multiflagellate.

Answer: 4. Multiflagellate.

NEET Botany Important Questions On Gymnosperms

Question 70. In cycas ovules are :

1. Orthotropous and unitegmic
2. Anatropous and unitegmic
3. Orthotropus and tritegniic
4. Anatropous and tritegmic.

Answer: 1. Orthotropous and unitegmic

Question 71. The largest sperms are found in:

1. Cycas
2. Gnetum
3. Pinus
4. Welwitschia.

Answer: 1. Cycas

Question 72. Which of the following is a living fossil?

1. Ginkgo
2. Abies
3. Pinus
4. Cedrus.

Answer: 1. Ginkgo

Question 73. Gymnosperms do not form fruits because they lack:

1. Pollination
2. Fertilization
3. Seeds
4. Ovary.

Answer: 4. Ovary.

NEET Botany Important Questions On Gymnosperms

Question 74. In gymnosperms, pollination is carried through:

1. Insects
2. Birds
3. Wind
4. Bats.

Answer: 3. Wind

Question 75. Which of the following is the best explanation for excurrent (pyramidal shape of pinus tree.)?

1. Effect of auxins on the growth of stem tip
2. Competition between adjacent trees for sunlight
3. Efficiency for water transport
4. Adaptation for wind pollination.

Answer: 4. Adaptation for wind pollination.

Question 76. Turpentine is obtained from:

1. Ferns
2. Gymnospemious wood
3. Angiospermous flowers
4. Angiospermous wood.

Answer: 2. Gymnospemious wood

Question 77. The seeds of cycas are :

1. Enclosed by fruit wall
2. Enclosed within flower
3. Naked and no fruit wall
4. Absent.

Answer: 3. Naked and no fruit wall

Question 78. Dwarf shoot of pinus is :

1. Shed every year
2. Shed after 2—3 years
3. Shed after five years
4. Never shed.

Answer: 2. Shed after 2—3 years

Question 79. Cycas occurs commonly in :

1. South america
2. North america
3. Southeast Asia
4. Europe.

Answer: 3. Southeast Asia

NEET Botany Important Questions On Gymnosperms

Question 80. Secondary wood in cycas is devoid of or (wood in cycas does not have the following):

1. Protoxylem
2. Vessels
3. Metaxylem
4. Tracheids.

Answer: 2. Vessels

Question 81. In pinus, the male gametes are :

1. Non-ciliate
2. Multiciliate
3. Biciliate
4. Uniciliate.

Answer: 1. Non-ciliate

Question 82. Multiciliated antherozoids occur in:

1. Riccia and funeral
2. Pteris and cycas
3. Riccia and pteris
4. Marchantia and riccia.

Answer: 2. Pteris and cycas

Question 83. Sulphur shower refers to :

1. Sulphur springs
2. The yellow colour of pollen grains
3. Pollen dust of pinus
4. None of the above.

Answer: 3. Pollen dust of pinus

NEET Biology Gymnosperms Questions

Question 84. In cycas:

1. Male strobilus (cone) and megasporophylls occur on separate individuals
2. Male strobilus and megasporophylls occur on the same individual
3. The same cone consists of both micro-and mega-sporophylls
4. The same sporophyll bears micro-sporangia and ovules.

Answer: 1. Male strobilus (cone) and megasporophylls occur on separate individuals

Question 85. Tracheids of cycas are with :

1. Uniseriate bordered pits
2. Biseriate bordered pits
3. Multiseriate bordered pits
4. None of the above.

Answer: 3. Multiseriate bordered pits

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 vs Angiosperms NEET

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 Examples For NEET

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 of P. 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 Classification NEET

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 Lifecycle NEET

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

Question 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

NEET Biology Non-Chordates Questions

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

NEET Biology Non-Chordates Questions

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.

NEET Biology Non-Chordates Questions

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

Animal Classification MCQs For NEET

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

Animal Classification MCQs For NEET

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

Animal Classification MCQs For NEET

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

Animal Classification MCQs For NEET

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.

NEET Previous Year Questions On Non-Chordates

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

NEET Previous Year Questions On Non-Chordates

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

NEET Previous Year Questions On Non-Chordates

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

Chapter-wise MCQs On Animal Kingdom NEET

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

Chapter-wise MCQs On Animal Kingdom NEET

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

Animal Phyla NEET Important Questions 

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.

Animal Phyla NEET Important Questions 

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

NEET Biology Non-Chordates Questions

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

NEET Biology Non-Chordates Questions

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.

Animal Classification MCQs For NEET

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

Animal Classification MCQs For NEET

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

Animal Classification MCQs For NEET

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

NEET Previous Year Questions On Non-Chordates

Question 30. The intermediate host of talent solium is :

1. Pig
2. Man
3. Sheep
4. Snail.