NEET Biology Elements Of Heredity Multiple Choices Questions

Question 1. When one member of a pair of allelic genes expresses itself as a whole, it is a case of:

1. Dominance
2. Co-dominance
3. Incomplete dominance
4. None of these.

Answer: 1. Dominance

Question 2. The first generation of a given cross is known as :

1. F₂ generation
2. F₂ generation
3. F₁ generation
4. None of these.

Answer: 3. F₁ generation

Question 3. Gamete is:

1. Diploid sex cell
2. Haploid cell
3. Diploid somatic cell
4. Triploid somatic cell.

Answer: 2.Haploid cell

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Question 4. The genotype of the individual is :

1. Genetic constitution
2. Genetic setup
3. Both of these
4. None of these.

Answer: 3. Both of these

Principles of Inheritance And Variation MCQs NEET

Question 5. Fraternal twins air produced when :

1. Two ova are fertilized simultaneously
2. Single fertilised ovum  gets fertilised again
3. Two ova develop paitlicnogcnclically
4. Single ovum fertilized by two sperms.

Answer: 1. Two ova are fertilized simultaneously

Question 6. “Theory of pangenesis” to explain the mechanism of heredity was given by :

1. Mendel
2. Darwin
3. Lamarck
4. Cuvier.

Answer: 2. Darwin

Question 7. The I.Q. of a genius ranges from :

1. 70-80
2. 90-109
3. 110-139
4. 140 and more.

Answer: 1. 70-80

Question 8. The genetic setup is termed as :

1. Dominant
2. Genotype
3. Phenotype
4. Alleles.

Answer: 3. Phenotype

Question 9. It is the ratio of mental age to :

1. Chronological age × 100
2. Chronological age + 100
3. Chronological age — 100
4. Chronological age ÷ 100.

Answer: 1. Chronological age × 100

Principles of Inheritance And Variation MCQs NEET

Question 10. The sex of an unborn mammal can be predicted by :

1. Placental biopsy
2. Examining the chorion
3. Amniocentesis
4. Examine the mother’s blood.

Answer: 3. Amniocentesis

Question 11. Criminal syndrome :

1. XXY
2. XO
3. XYY
4. XY.

Answer: 3. XYY

Question 12. Gallon is associated with :

1. Eugenics
2. Euthenics
3. Genetics
4. Human genetics.

Answer: 1. Eugenics

Question 13. The term gene refers to :

1. The sequence of amino acid
2. A linkage group
3. A part of tRNA
4. A portion of DNA.

Answer: 4. A portion of DNA.

Principles of Inheritance And Variation MCQs NEET

Question 14. Who connected cytology with genetics :

1. Morgan
2. Sutton
3. Bridges
4. Mendel.

Answer: 4. A portion of DNA.

Question 15. The total of genes in a population is known as :

1. Gene bank
2. Gene linkage
3. Gene pool
4. Genome.

Answer: 3. Gene pool

Question 16. Which is the wholly genetic trail?

1. Diphtheria
2. Leucoderma
3. Albinism
4. Tuberculosis.

Answer: 3. Albinism

NEET Biology Inheritance And Variation Questions

Question 17. The wife is a PTC non-taster and the husband is a PTC taster. Their son is a taster but daughters are non-tasters. This is not a sex-linked trait. Which pedigree is correct ?

Answer: 1

Question 18. Predict from the following chart 

1. Character is dominant and carried by X chromosome
2. Carried by Y chromosome
3. Character is sex-linked recessive
4. Character is recessive autosomal.

Answer: 3. Character is dominant and carried by X chromosome

Question 19. From the pedigree of a family given below, it is clear that the trait is inherited as a dominant autosomal trail. What will be the genotype of the mother and father?

1. Mother is aa and father is Aa
2. Father is AA and mother is aa
3. Father is Aa and mother is Aa
4. None of die above.

Answer: 1. Mother is aa and father is Aa

Mendelian Inheritance MCQs For NEET

Question 20. When an individual possesses both alleles of its phenotypically dissimilar parent, it is called:

1. Homozygous
2. Mother is aa and father is Aa
3. Dioecious
4. Monoecious.

Answer: 2. Mother is aa and father is Aa

Question 21. In a pig dominant allele B produces black colour and its recessive allele b produces white. What would be the probable genotype of the offspring when a cross is made between individuals heterozygous for colour?

1. BB
2. Bb
3. bb
4. All of these.

Answer: 4. All of these.

Question 22. When the phenotype and genotypic ratio resemble the E, generation, it is an example of:

1. Incomplete dominance
2. Dihybrid cross
3. Cytoplasmic inheritance
4. Linkage.

Answer: 1. Incomplete dominance

Mendelian Inheritance MCQs For NEET

Question 23. Word heredity is derived from the Latin word ‘Hereditas’ which means :

1. Heirship
2. Ancestral property
3. Blood relations
4. All the above.

Answer: 1. Heirship

Question 24. Which of the following explains the law of dominance?

1. The expression of only one of the parental characters in a monohybrid cross in the F( generation
2. The expression of both in the F₂ generation
3. The proportion of 3:1 obtained in the F₂ generation
4. All of above

Answer: 4. All of the above

Question 25. Starch grain size in pea seed is an example of:

1. Incomplete dominance
2. Multiple alleles
3. Pleiotropism
4. Polygenic inheritance

Answer: 1. Incomplete dominance

Question 26. In family. father had traits but their mother did not. All that ‘one and daughter bail this hail The same hail wav lound in some granddaughters, though daughter married lo normal persons.

In this pedigree the genotypes of lather, mother and husbands of daughters am

1. The father is AA, the mother is aa, husband are aa
2. Father is AA, mother is aa, and husbands are AA
3. Father is aa, mother is Aa, husband Aa
4. Father is AA. mother AA, one husband Aa and second husband aa.

Answer: 4. Father is AA. mother AA, one husband Aa and second husband aa.

Question 27. In sweet pea, genes C and P are necessary for colour in flowers. The flowers are white in the absence of either or both the genes. What will be the percentage of coloured flowers in the offspring of the cross Ccpp x ccPp?

1. 25%
2. 50%
3. 75%
4. 100%.

Answer: 1. 25%

Question 28. Polymorphism is mainly due to :

1. Monogenic inheritance
2. Polygenic inheritance
3. Both of the above
4. None of the above.

Answer: 3. Both of the above

Chapter-wise MCQs On Genetics And Heredity NEET

Question 29. Continuous genetic variations are produced by :

1. Independent assortment
2. Mutations
3. Climatic changes
4. Interspecific hybridization.

Answer: 2. Mutations

Question 30. The alleles that produce independent effects in heterozygous conditions are called:

1. Supplementary alleles
2. Codominant alleles
3. Epistatic genes
4. Complementary alleles.

Answer: 1. Supplementary alleles

Question 31. In the following pedigree chart, the mutant trait is shaded black. The gene responsible for the trait is:

1. Dominant and sex-linked
2. Dominant but autosomal
3. Recessive and sex-linked
4. Recessive and autosomal.

Answer: 2. dominant but autosomal

Chapter-wise MCQs On Genetics And Heredity NEET

Question 32. In the given pedigree, indicate whether the shaded symbols indicate a dominant or recessive allele.

1. Dominant
2. Recessive
3. Codominant
4. It can be recessive or dominant.

Answer: 3. recessive

Question 33. A dominant lethal gene Is that which

1. Allows nil organotin to survive and to tepfodiite
2. Allows an organism to sin vibe lull does not allow il to reproduce
3. Suppress the sex of the holder organism
4. Kills the organism in which it is present.

Answer: 4. Kills the organism in which it is present.

 Question 34. In humans, an example of a sex-linked trail is:

1. Sickle-cell anaemia
2. Curly hair
3. Down’s syndrome
4. Data are insufficient.

Answer: 1. Sickle-cell anaemia

Question 35. If the cell of an organism heterozygous for two pairs of genes represented by Aa,  undergoes meiosis, then the possible genotypic combination of gametes will be: 

1. AB, aB, Ah. ab
2. All, ab
3. Aa, Bb
4. Data are insufficient.

Answer: 3. Aa, Bb

Non-Mendelian Inheritance NEET MCQs

Question 36. To determine whether variations of a character in a population were genetically controlled, the most appropriate procedure will be lo :

1. Measure the variations and see if they are continuous or discontinuous
2. Crossing individuals of both extremes and sec if the offspring and  parents show the same range of variations
3. Count the chromosomes and find out the variations in their number in the population
4. Examine the DNA of F| progeny in a cross between AA and aa.

Answer: 2. Crossing individuals of both extremes and sec if the offspring and parents show the same range of variations

Question 37. If Mendel had studied the 7 traits using a plant with 12 chromosomes instead of 14, in what way would his interpretation have been different?

1. He could have mapped the chromosome
2. He would have discovered blending or incomplete dominance
3. He would not have discovered the law of independent assortment
4. He would have discovered sex linkage.

Answer: 3. He would not have discovered the law of independent assortment

Biology MCQs with Answers Question 38. How many different types of genetically different gametes will be produced by a heterozygous plant having the genotype: AAB b Cc?

1. Nine
2. Two
3. Four
4. Six.

Answer: 3. Four

Question 39. Human skin colour is controlled by several gene pairs. Let us assume here that there are just three gene pairs on different chromosomes and that for each pair there are two alleles – an incompletely dominant one that codes for melanin deposition and an incompletely recessive one that codes for no melanin deposition. If a very dark-skinned person marries a very light-skinned woman, what will be the chance that their offspring will have very dark skin?

1. 0
2. 1/4
3. 5/8
4. 9/64
5. 3/64.

Answer: 1. 0

Question 40. The F₂ generation offspring in a plant showing incomplete dominance, exhibits’

1. Variable genotypic and phenotypic ratios
2. A genotypic ratio of 1: 1
3. A phenotypic ratio of 3:1
4. Similar phenotypic and genotypic ratios of 1: 2: 1.

Answer: 4. Similar phenotypic and genotypic ratios of 1: 2: 1.

Non-Mendelian Inheritance NEET MCQs

Question 41. Two pea plants were subjected to cross-pollination. Of the 183 plants produced in the next generation, 94 plants were found to be tall and 89 plants were found to be dwarf. The genotypes of the two parental plants are likely to be :

1. TT and It
2. Tt and Tt
3. Tt and tt
4. TT and TT.

Answer: 3. Tt and tt

Question 42. Gametes are never hybrid? It is a statement of the law of:

1. Dominance
2. Segregation
3. Independent assortment
4. Random fertilization.

Answer: 2. Segregation

Biology MCQs with Answers Question 43. Which is correct about the traits chosen by Mendel?

1. The terminal pod is the dominant
2. The constricted pod is the dominant
3. Green coloured pod is the dominant
4. Tall plants are recessive.

Answer: 3. Green coloured pod is the dominant

Question 44. In a certain plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with an RRTt genotype is crossed with a plant rrtt genotype, what will be the percentage of tall plants with red fruits in the progeny?

1. 50%
2. 100%
3. 75%
4. 25%

Answer: 1. 50%

Question 45. Mendel obtained wrinkled seeds in pea due to the deposition of sugars instead of starch. It was due to which enzyme?

1. Amylase
2. Invertase
3. Dataset
4. Absence of starch branching

Answer: 4. Absence of starch branching

Question 46. The ratio of complementary genes is :

1. 9 : 3: 4
2. 12:3:1
3. 9 : 3 : 3: 4
4. 9:7

Answer: 4. 9:7

Question 47. When dominant and recessive allele express itself together, it is called :

1. Co-dominance
2. Dominance
3. Amphidominance
4. Pseudodominance.

Answer: 1. Co-dominance

Question 48. What is correct for blood group ‘O’?

1. No antigens but both a and b antibodies are present
2. An Antigen and b antibody
3. Antigen and antibody are both absent.
4. A and B antigens and a, b antibodies.

Answer: 1. No antigens but both a and b antibodies are present

Question 49. Sickle cell anaemia induces to:

1. Change of Amino Acid in α-chain of haemoglobin
2. Change of Amino Acid in β-chain of Haemoglobin
3. Change of Amino Acid in both a or β chain of Haemoglobin
4. Change of Amino Acid either a or β chain of Haemoglobin

Answer: 2. Change of Amino Acid in the β-chain of Haemoglobin

Question 50. Independent assortment of genes does not take place when :

1. Genes are located on homologous chromosomes
2. Genes are linked and located on the same chromosome
3. Genes are located on non-homologous chromosomes
4. All the above.

Answer: 2. Genes are linked and located on the same chromosome

NEET Biology Principles Of Inheritance And Variation

Genetics:(G.genesis_ descent) The study of the mechanism of inheritance and the control of the characteristics of an organism by its genes is called genetics. The name ‘genetics’ was first proposed by Bateson in 1906.

Heredity: (L he red inis = heirship). The transmission of characters, resemblances, and variations from one generation to another is called heredity.

Variations: The differences shown by the individuals of a species and also by the offspring of the same parents are referred to as variations.

Epigenetic Theory: A German zoologist, C.F. Wolff, proposed that neither the egg nor the sperm had a structure like a homunculus, but the gametes contained living substances capable of forming the embryo after fertilisation.

Magnetic power theory: Proposed by W. Harvey, it suggested that the utensils, through the friction of coitus, acquire some magnetic power to conceive an embryo. f-3 Kolreuter, the German botanist (1868), worked on crosses between different species of tobacco and gave some experimental evidence to prove that hereditary units tended to remain discrete in different generations.

Mendel: Mendel was the first to explain that heredity involved the transmission of units from the reproductive cells of the parents to the offspring.

Principles Of Inheritance And Variation NEET Notes

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Hugo de Vries, Correns, and Tschermak rediscovered the laws of Mendel and extended the work by experiments on various plants and animals.

• The physical basis of heredity is genes, present on chromosomes, and the chemical basis of heredity is DNA.
• Various pre-Mendelian concepts such as Moist vapour theory, Fluid Theory (Empedocles), Reproductive Blood Theory by Aristotle, and Preformation Theory (Malpighi). Theory of Pangenesis- Maupertius, had been proposed

NEET Biology Principles Of Inheritance And Variation Mendelism

Gregor Johann Mendel is called the ‘Father of Genetics’ and the study of principles of heredity’ laid down by Mendel is called Mendelism.

• Mendel was born in 1822 and became a schoolteacher in 1854.
• Mendel studied physics, mathematics, and the natural sciences at Vienna University.
• Mendel procured 34 varieties of pea that showed clear differences in characteristics and used them in breeding experiments.

The seven traits (characters) which interested Mendel were:

1. Length of stem (plant height),
2. Shape of seed,
3. Seed colour ;
4. Pod colour,
5. Pod shape,
6. Flower colour
7. Flower position.

Mendel studied the law of heredity. Mendel simply described the results of his crosses based on meiosis and fertilization and drew certain conclusions. Correns gave these conclusions the shape of laws.

• But his laws were rediscovered and finally got recognition in 1900 through the discoveries of Hugo de Vries, Carl Correns, and E.V. Tschermak.
• Mendel presented his “Experiments in Plant Hybridization” before the Brunn Natural Society on February 8, 1865. The society published Mendel’s research in 1866.

Mendel’s Law Of Dominance. This law states that the character that expresses itself in the F₁ generation is dominant, and the alternative character not expressed is recessive. The law of purity of gametes, also called the law of splitting of hybrids, states that each gamete receives only one gene of a trait.

Menders laws Of segregation: According to this law, the factors regulating character are separated during the formation, and hence only one of the pairs is transmitted by a particular gamete.

Mendel Law Of Independent Assortment: This law states that when there are two or more pairs of factors. The members of one of the factors segregate and assort independently of other pairs.

Principles Of Inheritance And Variation NEET Notes

NEET Biology Principles Of Inheritance And Variation Terminology Used In Genetics

Gene: According to Mendel, a gene (factor or determinant) is a unit all is ivs|vnsiMe tor die transmission and expression of a hereditary trait. A gene has two different forms or alleles.”
Or
The concept of the gene resulted from a convergence of cytology and genetics is gene is a segment of chromosomes which acts as a carrier of characters.
Or
Gene is a segment of nucleic acid that is responsible for the transmission and expression of a hereditary trail. A gone may have a large number of hereditary alleles that arise by mutation or by recombination.
Or
Gene is a segment of DNA which expresses itself by directing the synthesis of specific polypeptides.

• The term gene was given by Johannsen (in 1909). A gene is a unit of inheritance which is carried from a parent by a gamete in a chromosome and controls the expression of a specific character in the young one.
• Genotype: It refers to the genetic makeup of an organism (Johannsen 1909). Genotype is the gene complement or genetic constituent of an individual about one or more characters irrespective of whether genes are expressed or not.

Phenotype: (Johannsen, 1911) It is a measurable or observable distinctive structural and functional characteristic of an individual about one or more characters which is a result of gene products brought to expression in a given environment.

• The characteristic may be visible to the eyes Example (the height of a plant) or may require speculation for its identification (for example., a serological test for a blood group.)
• The tall pea plants have two types of genetic combinations (TT and Tt). Irrespective of the genetic set up they develop the same character. Thus phenotype is dependent upon genotype and expressibility of its genes.

Alleles or Allelomorphs: (Allele-belonging to one another). It is used to refer to one member of a gene pair.

• According to Mendel, two genes representing two alternatives of a character are present on two separate chromosomes of a homologous pair but at the corresponding loci Example in the gene pair, A (tall) is present on one chromosome and (dwarf) is on the other chromosome.
• Each of them is called an allele, i.e. T. an allele to T and vice versa.
• Pseudoalleles: Genes having separate but nearby loci and controlling the same trait In Drosophila, the genes for apricot and white eye colour are pseudoalleles. Duplicate Genes.
• Two pairs of genes lie in different chromosomes and produce a single trait with or without a cumulative effect. The coat colour in the Duroc-jersey breed of pigs depends on 2 pairs of genes.

Lethal Genes: Genes that make the organism having them inviable to live. In the yellow race of mouse, Mus musculus, the genes YY kill the embryos.

Atavism (Reversion). Occasional reappearance of a remote ancestral trait in some individuals. Example A short tail in some babies.

Dominant Factor: A heterozygote possesses two contrasting genes but only one of the two can express itself while the other remains hidden.

• The gene which gains expression in the F₁ hybrid is known as the dominant Example (T is dominant and masks the t).
• Recessive factor: The factor of an allelomorphic pair which is unable to express itself in the presence of its contracting factor is called the recessive factor in the case of Tt.
• Wild type: The commonly occurring phenotype in the natural breeding population is called wild type.

Hoinozvgotc: It is the individual whose homologous chromosomes bear identical genes or alleles of a given allelic pair and produces gametes all example RR.rr, TT. u.TTRR etc.

Heterozygote: It is the individual whose homologous chromosomes bear unidentical or dissimilar genes or alleles of a given allelic pair and produces dissimilar or different types of gametes, for example, Tt, Rr, Tt Yy etc. (The number of the types of gametes produced by heterozygote can be found out by the formula 2n where ‘n’ stands for the number of pairs of contrasting characters present in the heterozygote). It is also called hybrid.

Mendelian Inheritance NEET

• Hybrid vigour or Heterosis: It is the increased vigour or strength of the hybrids than their parents. It is of superior quality to either of the parents.
• Pure Line (Johannsen, 1900). The series of generations of organisms or descendants which breed true because they are derived from a single self-fertilized homozygous ancestor or identical homozygous ancestors (members of a pure line are therefore homozygous for one or more characters).
• Linkage: Linkage was first seen by Sutton. Term linkage was given by Morgan. It is the phenomenon of staying together of certain genes during inheritance through several generations without any change or separation.
• Back Cross: It is a cross which is performed between a hybrid and one of its parents. In plant breeding, a back cross is performed a few times to increase the traits of that parent.

Test Cross: It is a cross to know whether an individual is homozygous or heterozygous for a dominant character. The individual is crossed with a recessive parent.

• The offspring will be 100% dominant if an individual is homozygous dominant. The ratio will be 50% dominant and 50% recessive in the case of hybrid or heterozygous individuals.
• Thus monohybrid test cross ratio is 1:1 In case of double heterozygote (Rr Yy) crossed with double recessive (rryy) the ratio will be 1:1:1:1.

Out Cross: Cross between F₁ individuals and homozygous dominant parent to improve or produce hybrid plants which are superior to parents, we make out-cross.

• Eugenics: The application of genetics in an attempt to improve the hereditary qualities of humans.
• Gene locus: Location of a particular gene (or one of its alleles) on a chromosome.
• Polyploidy: Having three or more complete sets of chromosomes.
• Qualitative inheritance: It is a type of inheritance in which a single gene influences a complement.

Mendelian Inheritance NEET

Penetrance: A genotype can produce its phenotype in an individual. It is of 2 types :

1. Complete Penetrance Full expression of a genotype in an individual. In humans, the allele B for brown eyes and the allele b for blue eyes have complete penetrance in the homozygous condition, BB, bb. The allele B has complete penetrance even in the heterozygous condition, Bb also.
2. Incomplete (Reduced) Penetrance. Failure of a genotype to express in all cases. In humans, diabetes Mellitus is genetically controlled. However, not all persons carrying the genes for this disorder develop it.

Relation among pairs of independent alleles Gametes F₂ genotypes and F₂ phenotypes when domainer is prevented:

Self Stecrility: Hound in plants having multiple alleles for compatibility incompatibility reaction – S₁, S₂, S₃, S₄, S₅, S₆, etc. A plant carries two such allelesExample S₁, S₂, S₂, S₃, S₁, S₃,S₂,S_4,S_3,S₅.

• A pollen grain carries only one allele. If it happens to be one of the two alleles of the pistil, the pollen grain fails to form a pollen tube.
• Heterodominance or Overdominance or Superdominance: Scrra( 1959) described when F₁ generation heterozygotes have a more complex phenotype than that of a corresponding parent, it is termed hetero-dominance.

F₁ Generation: The F₁ or First filial (Filus — son and filial—daughter) generation is the generation of hybrids produced from a cross between two genetically different individuals called parents as Tt individuals are produced from a cross between TT and tt parent.

F₂Generation. F₂ or Second filial generation is the generation of individuals which arises as a result of inter-breeding amongst individuals of the F₁ generation.

• Principle of Paired Factors. Each character is represented in an individual by two determinants, factors or genes. They are similar in homozygous individuals which breed true. The factor or a character represents two alternatives of a trait in hybrids.
• Monohybrid Cross: It involves the study of the inheritance of one pair of contrasting characters.
• Monohybrid Ratio: It is the ratio obtained in the F₂ generation when a monohybrid cross is made and the offspring of the F₁ generation are self-bred. Monohybrid ratio is usually 3 :1 (phenotypically) and 1: 2 :1 (genotypically).
• Dihvbrid Cross: It is a cross between two organisms of a species which is made to study the inheritance of two pairs of characters.

Trihybrid Cross: A cross between homozygous parents that differ in three gene pairs (i.e. producing trihybrids) is a combination of three single-pair crosses operating together. Thus (AA x aa), (BB x bb) and (CC x cc) could be combined in the same cross.

Principles Of Inheritance And Variation NEET Notes

• Dihybrid Ratio: It is the ratio obtained in the F9 generation when a dihybrid cross is made and the offspring of the F₁ generation are self-bred. Phenotypically it is 9:3:3:1.
• Trihybrid ratio: Ratio in F₂ obtained in a trihybrid cross represented by a Punnet square. 64 (8n) squares would be required with a phenotypic ratio of 27:9:9:9: 3:3:3:1.
• Polyhybrid Cross: It includes those characters in which inheritance of more than two pairs of genes are considered.
• Reciprocal Crosses: These crosses involve two concerning the same characters but with reversed sexes. It means if in a first cross, A is used as the female parent and B as the male parent, then in 2nd or reciprocal crosses A will be used as the male parent and B as the female parent.

Punnet Square: It is a chequerboard used to show the results of a cross between two organisms. The chequerboard was devised by R.C. Punnet. It depicts both the genotype and phenotype of the progeny.

• Dihybrid: An individual that is heterozygous for two pairs of alleles. The progeny of a cross between homozygous parents differs in two respects.
• Homozygous: The condition in which only one allele of a pair is present, as in sex linkage or as a result of deletion.

The formula for number of genotypes in case of multiple alleles is \(\frac{n}{2}(n+1)\) = n Alleles. i.e. in the case of the blood group system, 3 alleles regulate the ABO blood group thus number of the genotype formed will be six.

• If a cross is made between two yeasts having genotype Aa Bb Cc. then the probability of getting genotype aa bb cc will be 1/64 because if we consider individuals the probabilities of occurring of aa, bb and cc is — \(\frac{1}{4}\) therefore = \(\frac{1}{(4)^3}=\frac{1}{64}\)
• Three genotypes are produced by two alleles.
• Even Aa Bb Cc DD Ee Ff produces 32 different gametes.
• A recessive allele in the zygote appears only if both parents possess this allele.
• Progeny = offspring ir
• Siblings or sibs, Individuals having the same parents, brothers and sisters.

Mendelian Inheritance NEET

NEET Biology Principles Of Inheritance And Variation Modifications Of Mendelian Ratio And Gene Interaction

Gene interaction. It is the influence of one gene (allele) over another which causes a change in expression, and phenotype of normal Mendelian ratios like 3: 1 (monohybrid cross) and9:3:3:l(dihybrid cross.).It may be intragenic (intr alleles) or intergallic (non-allelic). They are of the following types :

• ID Incompletedominance (Intermediateinheritance). It is the phenomenon where none of the two Mendelian factors, alleles or genes is dominant over the other.
• Genotypic and phenotypic ratios are the same in the F2 generation i.e. 1:2:1. Example. Illustrated in Mirabilis jalapa (Four o’clock), Antirrhinum (Snapdragon or Dog flower) and Andalusian fowls.
• In a dihybrid cross if one trait follows the law of dominance the other shows incomplete dominance, the ratio comes to be 3: 6: 3:1 : 2: 1 and if both traits show incomplete dominance, it will be1: 2:1: 2: 4: 2: 1.
• Codominance. It is the equal and independent expression of two alleles of a trait when they are present together in an individual. The phenotype of a heterozygous individual is different from either of the homozygous.
• Example. A, B, AB and O blood group.

Genetic Disorders And Variation NEET

Duplicate Genes (15: 1) Observed by G.H. Shell Pseudoalleles or Duplicate genes or factors are two or more independent genes present on different chromosomes which determine the same or nearly the same phenotype in a dominant state so that either of them can produce the same character. The independent genes do not have a polymetric effect, e.g. Endosperm colour in maize, fruit shape in Shepherd’s’ purse, and inheritance of grain colour in Avena sativa (Oat).

• Polymetric or Additive genes (9:6: 1). They are duplicate genes with cumulative effects. Two independent dominant genes, whether present in homozygous or heterozygous conditions have similar phenotypic effects when present individually but produce a cumulative or double effect when found together for example Summer squash plant (Cucurbita pepo) has three types of fruit forms.

Polygenes (Quantitative inheritance) or Multiple genes or Cumulative genes. There are many characteristics in both plants and animals which are controlled by the cumulative action of dominant alleles of generally two or more independent genes for example., height, weight, size of fruits, number of grains in an ear, skin colour in mah.

NEET Principles Of Inheritance And Variation Chapter Notes

Illustrations of Polygenes in Human Skin Colour

• Human skin colour is controlled by the polygenic effect of at least three separate genes.
• Each gene contributes to a unit of darkness’ due to incomplete dominance. ‘
• Skin colour is determined by cumulative genes and this hypothesis was designed by Davenport and Davenport in 1910.
• Davenport and Davenport designated five phenotypic classes controlled by genes A . and B (like kernel colour of wheat)

Hughes (1944) recognized seven phenotypic classes designating genes A, B and C.

• The skin shades vary from very dark in AABBCC individuals to very light in an aabbcc individual.
• A person with AaBbCc (i.e. heterozygous for all three genes) will have an intermediate colour termed mulatto.
• The number of possible allele combinations in the gametes is eight (ABC, ABc, AbC, aBC, abC, aBC, abe. abc) for such a person.
• So a total of 64 phenotypic combinations is possible when two persons of ABC x abc gene combinations marry.

Genetic Disorders And Variation NEET

NEET Biology Principles Of Inheritance And Variation Characteristics Of Polygene

1. Negligible effect of environment.
2. No involvement of linkage and epistasis.
3. The quality of the gene does not matter.
4. Each contributing gene (allele) in a series produces an equal effect.
5. The effect of each contributing gene is additive (cumulative).

Short Cut Method To Predict The Phenotype Ratio Of Polygenic Inheritance :

• We should know the numbers of total alleles involved in a quantitative inheritance to predict the phenotype ratio of F-, generation.
• This prediction can be shov/n with the help of Pascal’s triangle: e.g. Kernel colour of wheat there are 4 alleles and a ratio of 1: 4 : 6: 4: 1 is obtained.
• Nilsson-Eble (1908) obtained the first experimental proof of polygenic inheritance.

Dihybrid And Monohybrid Cross NEET

Some Ratios Of Polygenic Inheritance:

Quantitative or polygenic inheritance was first studied by J. Kolreuter in the case of tobacco and F. Galton in the case of human beings, Nilsson-Ehle in kernel colour in wheat and Emerson and East studied it in cob length in maize. Davenport studied skin colour in man

The relative contribution of each polygene

= \(\frac{\text { Maximum height }- \text { minimum average height }}{\text { Total number of polygenes }}\)

• Complementary genes (9:7) (Bateson and Punnet 1906). These non-allelic genes independently show a similar effect but produce a new (rail when present together in dominant form for example., flower colour in sweet pea, grain colour In lice, grain colour in Sorghum.
• Supplementary genes (9:3: 4): They are a pair of non-allelic genes; one of which produces its effect independently when in the dominant state while the dominant allele of the other is without any independent effect but can produce a new trait along with the dominant allele of the form example Glume colour in Sorghum emulation, Seed colour in Lab lab, Coat colour in mice and guinea pig.
• Collaboration: Epistasis of complementary and supplementary genes produces a ratio of 27: 37. c.g. Maize colour pigment anthocyanin is due to two complementary genes and one supplementary gene.

Principles Of Inheritance And Variation Class 12 Notes For NEET

Epistasis: It is the phenomenon of masking or suppressing the expression of a nonallelic gene. The gene which suppresses other non-allelic genes is called the epistatic gene while the gene or locus which is suppressed by the non-allelic gene is called the hypostatic gene.

• Dominant epistasis (12: 3:1): The dominant allele at one locus suppresses the expression of another gene regardless of its allelic condition ( dominant or recessive)Example Fruit colour in cucurbita (yellow, green and white), coat colour in the dog (White, black and brown).
• Recessive epistasis (9:3:4): In this case, recessive homozygous genotype at one locus (aa) suppresses the expression of non-alleles at another locus. The latter can produce their effect only when a dominant allele occurs at the first example Pigmentation in onion bulb, and coat colour in mice.
• Dominant-recessive epistasis (13 : 3): Here the dominant allele at one locus (A-) and recessive allele at another locus (bb) give rise to the same effect. (A-B, A-bb, aabb) other gene combinations produce different phenotypesExample Plumage colour in poultry birds.

Summary Of Epistatic Ratios:

Lethal genes. These genes kill the organism when they can express their effect. Dominant or homozygous recessive, for Example, Sickle cell anaemia, Fur colour in mice (first studied by Cuenot in 1905)

Dihybrid And Monohybrid Cross NEET

• E. Baur. Observed lethal genes in. Snapdragon (Antirrhinum) ill Yellow Lethals in Mice
• Lucien Cuenot (1905) reported an incompletely dominant allele Y for yellow coats in mice.
• ‘A’ represents a gene for yellow and ‘n’ one for black.
• W. Castle and C. Little (1910) proposed that the yellow homozygotes were aborted in the uterus.
• In other words, the yellow allele has a dominant effect on coat colour but acts as a recessive allele concerning the lethality phenotype.

Albinism In Corn (Zea mays)

• Albinism in corn is due to a lethal gene.
• The gene ‘G’ is for normal chlorophyll production. It is completely dominant to its allele.
• G plants contain chlorophyll and are photosynthetic.
• On the other hand, gg plants produce no chlorophyll and are yellowish white and die.

Pleiotropic Genes: These genes have multiple effects because they influence several traits simultaneously.

Examples

1. Marphan’s syndrome is caused in human beings by a pleiotropic gene which is characterised by a slender body, limb elongation, hypermobility in joints, lens dislocation and a tendency to develop heart diseases.
2. Sickle cell anaemia. Sickle cell anaemia disease is caused by gene (Hbs) which is lethal in the homozygous condition but has a slightly detectable effect in the heterozygous condition. In sickle cell anaemia, a change in the shape of red blood cells occurs in the venous blood.

Being deficient in oxygen tension, these erythrocytes show a marked change in their structure attaining a sickle-shaped structure. As a result, rupturing of cells may take place and chronic haemolytic anaemia is caused.

• This disease is caused when the gene responsible for haemoglobin produced by recessive alleles differs in one amino acid i.e. it incorporates valine in place of glutamic acid, at the 6th position of the β-chain.
• Sickle cell anaemia is common in persons of African descent and is also found in some other parts of the world where malaria is, or has been major cause of death.
• In heterozygotes Hb^AHb^S, some red cells contain haemoglobin A, and other haemoglobin S. Because both types of haemoglobin, rather than a single intermediate form are produced, it is also a case of codominance.
• Under normal conditions, heterozygotes manifest none of the severe symptoms of HbsHbs persons, though they may suffer some periodic discomfort and even develop anaemia after a time at high altitude.

Principles Of Inheritance And Variation Class 12 Notes For NEET

Explanations for various genotypes are :

• Hb^AHb^S — Normal (Haemoglobin A only: no sickling)
• Hb^AHb^S — Sickle cell trait (Haemoglobin A and S: sickling under reduced oxygen tension)
• Hb^SHb^S — Sickle cell anaemia (Haemoglobin S only: sickling under normal oxygen tension)

Sickle cell anaemia can also be considered a case of lethal genes.

• A lethal gene can be defined as a gene whose phenotypic effect is sufficiently drastic to kill the bearer.
• The expected ratio in lethal gene cases comes equal to 2: 1.
• In sickle cell anaemia, death is caused by Hb^SHb^S condition.

Multiple Alleles:

Genes possessing multiple alternative forms, such as 15 alleles for eye color in Drosophila.

• Four alleles determine coat colour in rabbits. ABO blood groupings.
• Multiple alleles exhibit the following characteristics
• Several alleles are situated at the identical locus on the chromosome.
• Several alleles govern a specific trait.
• Crossover events do not occur across multiple alleles since they occupy the same locus.
• Multiple alleles can exhibit dominant or intermediate traits, but the wild type in the series is often dominant.
• Wild type or dominant alleles are denoted by uppercase letters, whereas recessive alleles are indicated by lowercase letters

Blond groups:

Viv determined by two types of antigens (A and B) present on the surtax coating to R.B.C.These antigens occur in the oligosaccharides-rich head regions of a glycophorin.

Principles Of Genetics NEET Notes

Showing phenotype, genotype and antigen.

• Additive Factors: Polygenes affecting the same trait, with each enhancing the phenotype.
• Concordance: Identity of matched pairs or groups for a given trait; for example, identical twins both expressing the same genetic syndrome.

NEET Biology Principles Of Inheritance And Variation Revision Notes

NEET Biology Principles Of Inheritance And Variation Important Contributors

E. Haeckel:

Inheritance transmission via the nucleus.

• Pythagoras: He posited the hypothesis of moist vapour.
  Empedocles proposed that each bodily portion generated a fluid, so introducing the fluid theory of inheritance.
• Aristotle proposed the hypothesis of reproductive blood.
• Darwin posited that each somatic cell and tissue in the body generates minute particles known as gemmules or pangene, which encapsulate both hereditary and acquired traits.
• Leeuwenhoek: First observed spermatozoa.
• Malpighi posited that a homunculus, or miniature individual, exists within sperm or egg cells.
• Maupertuis proposed the notion of pangenesis, positing that heredity is governed by minute particles.
• Kolreuter, a German botanist. He produced viable interspecific hybrids in tobacco. He is the ‘‘father of polygenic inheritance.”

Gregor Johann Mendel. Father of genetics as he was the first to demonstrate the mechanism of transmission of characteristics and biochemical disorders of man.

• Johannsen. Coined the terms gene and genotype, phenotype and pure line.
• Gallon. Started pedigree analysis.
• R.C. Funnel. Used a chequerboard called Punnet square to show the results of a cross between two organisms.
• Sir Archibald Garrod. Studied ABO blood types.
• F. Gallon. He studied polygenic inheritance in man and coined the term eugenics.
• Nilsson-Ehlc. Obtained the first experimental proof of polygenic inheritance in the case of kernel colour of wheat.
• Karl Landsteiner. (1907) discovered A. B, O blood groups.
• Gastello and Steini (1902) discovered the A B blood group.
• Kolreuter: (German botanist). He obtained fertile interspecific hybrids in tobacco. He is the “father of polygenic inheritance.
• Karl Landsteiner and Weiner discovered the Rh Factor.
• Corrrens, de Vries and Tsechermak rediscovered Mendel’s theory ol inheritance. Also discovered incomplete dominance and cytoplasmic inheritance.

Principles Of Genetics NEET Notes

NEET Biology Principles Of Inheritance And Variation Some Important Ratios

Principles Of Genetics NEET Notes

NEET Biology Principles Of Inheritance And Variation Variations

All living beings exhibit variations in practically every character and almost all directions.

• The differences shown by the individuals of a species also by the offspring of the same parents are referred to as variations.
• All organisms change themselves to adapt themselves to the changing environment, otherwise they fail to survive. Variations are classified in two ways i.e.

As per the nature of the cells, it affects.

Somatic variations. Such variations are not inherited from parents and affect the omalic cells only.

• They are acquired by an organism during its lifetime and are lost with death Hence, such variations are also called acquired variations. There are possible causes for such variations :

Three possible causes of acquired variations are :

1. Environmental Factors i.e. medium, light, temperature, nutrition and water.
2. Use of disuse of organs
3. Conscious efforts

Germinal variations (Blastogenic Variations). These variations cause the line to grow cells and are thus inheritable for haemophilia, blood groups, colour-blindness, hairiness, eve vvIihii etc SikIi satiations may be due to the following reasons. As per the degree of difference produced. 2 types

1. Merstic = Influence the mnnlicr of parts
2. Substantive = Inllncnec the shape, size, weight and colour.

Continuous sanctions: Variation not represented by distinct classes. Individuals grade into each other and measurement data are required for analysis (cf. Discontinuous variation), Multiple genes or polygenes are usually responsible for Ibis type of variation, (or Fluctuating variations).

• Discontinuous variations. Distinct classes such as red versus white, tall versus dwarf (rf. Continuous variation).
• Transgressive variation. The appearance in (lie F₂ (or later) generation of individuals, showing n more extreme development of a trait than shown in either original parent. It is due to polygenic inheritance discovered by Punnet and Hailey.
• Determinate Variations (Orthogenic variation). Adaptive and selective variations of definite evolutionary lines, developing progressively generation after generation.
• Indeterminate variations. Variations occurring in any conceivable direction and are not governed by any law may give a distinct advantage to the possessor in its light for existence.

Techniques Used To Study Lutinuii Genetics

1. Pedigree analysis
2. Population genetics
3. Human karyotype.

Pedigree analysis: Pedigree is a record of the inheritance of certain traits for two or more generations presented in the form of a diagram family tree or symbols. Different symbols used are.

• The idea dial disorders are inherited has been prevailing in human society for a long. Dus was based on the heritability of certain characteristic features in families.
• After the rediscovery of Mendel’s work, the practice of analysing the inheritance patterns of traits in human living began.
• Since it is evident that control crosses that can be performed in plants or some other organisms, are not possible in the case of human beings, the study of the family history about inheritance of a particular trail provides an alternative.
• Such an analysis of traits in several of generations of a family is called the pedigree analysis. In the pedigree analysis, the inheritance of a particular trait is represented in the family tree over generations.
• In human genetics, pedigree study provides a strong tool, which is utilised to trace die inheritance of a specific trait, abnormality or disease.

Population genetics:

• It is the study of the distribution of units and the frequency of genes within the total population.
• The formula delineating the genotypic expectations of progeny in relation to the gametic (allelic) frequencies of the gene pool was proposed by Hardy and Weinberg and is referred to as the Hardy-Weinberg principle.

Principles Of Inheritance And Variation NEET Notes

This law is applicable only if:

1. Populationis is large and pamniclie (Random matiing).
2. No selecting, no imitation.
3. Population is closed.

under these conditions, according to Hardy and Weinberg’s Law. there.should be no change in the gametic or zygotic frequencies from generation to generation.

Expected genotype pic (zygotic) frequencies in generations may be summarised as

⇒ (p+q)²=P²+2pq+q²=1.0

⇒ P² = frequency of dominant gene/alleles.

⇒ q² = frequency of recessive gene/alleles P=k=1

⇒ p² + 2pq = frequency of dominant trait.

⇒ q² = frequency of a recessive trait.

Human Karyotype: Tjio and Levan first prepared a human karyotype.

• It is an arrangement of chromosomes according to the length of chromosomes and the position of the centromere.
• A pencil sketch or photograph of a karyotype is called an idiogram.
• It is an asymmetrical karyotype which is considered an advanced character.

Principles Of Inheritance And Variation NEET Notes

Classification of chromosomes: The human metaphase chromosomes were First of all classified in a conference of cytogeneticists at Denver, Colorado in I960.

• In humans 23 pairs (46) chromosomes have been numbered from l to 23 according to their decreasing size, Patau (I960) divided the human chromosome into the following seven groups designated A to G.

• Banding Technique: It is the development of risk ami light band of stains on the chlorosome when they are treated with special fluorescent lives.
• Hits are because different parts of the chromosome show differential affinity to these stains.
• Chromosome handling was discovered by Caspersson et al (1970) and Paridue and Galt(1970) almost simultaneously late as different types of stains and staining techniques.
• Each develops a unique banding pattern which remains constant.

Mendelian Inheritance NEET

• Continuity of life is made possible by asexual and sexual reproduction Sexual reproduction, besides creating new individuals introduces variability in the offspring by combining trials of parents.
• The genotypic ratio of the dihybrid cross is RRYY: RrYY : RRYy: rrYY: RrYy : rrYy: ItRyy : Rryy: rryy 1:2: 2:1:4:2:1:2:1
• In the case of MN blood groups in humans, alleles show codominance. The red blood cells can carry two types of native antigens, M and N, and an individual can be MM, MN or NN exhibiting either one or both of them
• ABO blood group system shows codominance, multiple alleles and dominant recessive gene interaction.
• Treatment with gibberellic acid only brings phenotypic changes and genes are not affected.
• Pleiotropy results in different expressions at the phenotypic level. For example, sickle cell anaemia and cystic fibrosis in men.
• Morgan is called the father of experimental genetics. Bateson is called the father of modern genetics. Nilsson-Ehle (1908) was the first scientist to prove quantitative inheritance.
• At the time of fertilization, the chance factor is responsible for the fusion of gametes. Infinite new combinations are produced Example 70 × 10¹² for 23 pairs of chromosomes.

Cause Of Variations Is Hidden In Sexual Reproduction

Mendel’s Laws of Inheritance:

1. Law of paired factors
2. Law or Principle of Dominance Law of Segregation.
3. Phenotypic ratio = 3:1 Monohybrid genotypic ratio =1:2:1
4. Law of Independent assortment Dihybrid phenotypic ratio = 9 : 3 : 3: 1 Dihybrid  genotypic ratio = 1: 2 : 1: 2 : 4: 2 : 1: 2: 1

Exceptions To Mendelism

• Incomplete Dominance = Genotypic and phenotypic ratio =1:2:1
• Codominance. I^AI^A (In the case of blood groups)
• Hb^AHb^A (In case of sickle cell anaemia)
• Multiple alleles. 15 alleles for eye colour in Drosophila, 3 alleles for blood groups in humans (I^A, I^A and 1° for four types of blood groups (A, B, AB and O.)
• Chromosomal theory of inheritance proposed by Sutton and Boveri (1902)
• Experimental verification by Morgan with his experiments on Drosophila melanogaster.
• Linkage. Physical association of two genes on a chromosome.
• Recombination. Generation of non-parental gene combination.
• Sex Determination.

Genetic Disorders And Variation NEET

Human : Autosomes + XY → Male, Autosomes + XX → Female

Most of the insects (Male heterogamy).

• Grasshopper AA + XO → Male
• AA + XX → Female
• Birds AA + ZW → Female
• AA + ZZ → Male

Mutation

1. Chromosomal mutation
2. Point mutation — Sickle cell anaemia
3. Frameshift mutation.

Mutagen—Physical agents which cause mutation: UV radiation and Chemical Mutagen.

Pedigree Analysis Male and Female Analysis of Traits.Marriage between close relatives 0=0

NEET Biology Principles Of Inheritance And Variation Study Material

NEET Biology Principles Of Inheritance And Variation Elements Of Heredity And Variations Conclusion

In sickle cell anemia, glutamic acid is substituted by valine at the sixth position in the β-chain of haemoglobin.

• In thalassemia, a genetic blood condition characterized by anemia, the β-chain of haemoglobin is altered due to a frameshift mutation. Bone marrow is absent.
• Either the mother must be Rh positive, or both the mother and the husband must be Rh negative; otherwise, the second kid may suffer erythroblastosis fetalis.
• Rh positive is genetically prevalent in humans.
• The back cross is a genetic cross formulated by Mendel in which the F1 generation is mated with an individual possessing the same genotype as one of the parental organisms.
• The colouration of sweet pea flowers is attributed to a substance known as anthocyanin. It is released by a sequence of metabolic processes involving distinct enzymes.

The formation of each enzyme is determined by separate genes the mutant white tigers now seen in Indian zoos, a defective pleiotropic gene influences both fur colouration and the connection between the eye and brain during development.

• The trihybrid ratio shows the same pattern of inheritance as the dihybrid. The phenotype ratio will be 27: 9 : 9: 9 : 3 : 3 : 3: 1.
• When the heterozygotes have a more extreme phenotype than either of the corresponding homozygotes, then it is usually called over-dominance, super-dominance and hetero-dominance.
• Parasexual hybridisation. It is defined as the technique of hybridisation through protoplast fission. The protoplast fusion opens up the possibility of overcoming the sexual barriers and of mixing and reassorting the genetic element of sexually isolated organisms

• Mendel used the word unit factor or pair factors for controlling units by various traits because he was unaware of the word gene.
• Epistasis is a Greek word which means the act of stopping or inhibiting.
• Non-allelic genes are those present in different loci.
• Genealogy: The history of descent of a person or its family is termed genealogy.
• Modifier Genes: Genes that alter or modify the expression of other non-allelic genes. Modifier genes produce a variety of crests on pigeons’ heads.

NEET Biology Enzymes

Enzymes. serval definitions given for enzymes are as follows:

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

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

Read and Learn More NEET Biology Notes

Enzymes Notes For Neet

Discovery of enzyme

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

Properties

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

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

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

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

NEET Biology Nomenclature And Classification Of Enzymes

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

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

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

Enzymes Notes For Neet

Major Classes of Enzymes

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

NEET Biology Some Terms Regarding Enzymes

Isozymes (Isoenzymes):

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

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

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

Factors Affecting Enzyme Action

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

Enzyme Classification And Functions Neet

Regulation of Enzyme Action

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

NEET Biology Commercially Important Enzymes

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

Significant Historical Facts of Enzymes

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

Enzyme Classification And Functions Neet

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

Enzyme Inhibition And Regulation Neet Biology

Quanta to memory

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

Turn over Numbers

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

Enzymes Identified with Hereditary Disease

Multiple Choice Questions on Enzymes – NEET Biology

Question 1. As the temperature changes from 30 to 45’c the rate of enzyme activity will:

1. Decrease
2. First decrease and then increase
3. First increase and then decrease
4. Increase.

Answer: 3. First increase and then decrease

Question 2. Which one inactivates an enzyme by changing the enzyme’s shape?

1. Non-competitive inhibitor
2. Competitive inhibitor.
3. Coenzyme
4. All the above.

Answer: 1. Non-competitive inhibitor

Question 3. A non-proteinic enzyme is :

1. Lysozyme
2. Zymase
3. Papain
4. Rna ase-p.

Answer: 4. Rna ase-p.

Question 4. Which of the following belongs to class 5 of the cubic system of classification of enzymes?

1. Isomerase
2. Ligases
3. Transferase
4. Lyases.

Answer: 1. Isomerase

Read and Learn More NEET Biology Multiple Choice Question and Answers

Question 5. Which does inactivate by denaturation in it?

1. Allosteric inhibitor
2. Competitive inhibitor
3. Irreversible inhibitor
4. None of the above.

Answer: 1. Allosteric inhibitor

Question 6. Most of the enzymes are secreted in an inactive form, otherwise, they will be destroyed.

1. Cell proteins
2. Cell dna
3. Cell mitochondria
4. Cell wall and membrane.

Answer: 1. Cell proteins

Multiple Choice Questions On Enzymes Neet

Question 7. The fastest enzyme is :

1. Pepsin
2. Trypsin
3. Catalase
4. Carbonic anhydrase.

Answer: 4. Carbonic anhydrase.

Question 8. Buchner isolated

1. Siamese
2. Zymase
3. Zeatinase
4. Ferment.

Answer: 2. Zymase

Question 9. The best example of extracellular enzymes (exoenzymes) is:

1. Nucleases
2. Digestive enzymes
3. Succinic dehydrogenase
4. None of the above.

Answer: 2. Digestive enzymes

Question 10. Enzymes bring about hydrolysis of esters and peptides are :

1. Transferases
2. Lyases
3. Hydrolases
4. Ligase.

Answer: 3. Hydrolases

Question 11. Examples of amine online are:

1. Arginase
2. Lactase
3. Zymase
4. Lipase.

Answer: 1. Arginase

Question 12. Energy must be added to a chemical reaction to start. This energy is known as the energy of :

1. Entropy
2. Activation
3. Enthalpy
4. Oxidation.

Answer: 2. Activation

Multiple Choice Questions On Enzymes Neet

Question 13. Which level of ‘x’ represents the usable energy yield?

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

Answer: 2. 2

Question 14. Which segment of ‘x’ represents the energy of activation?

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

Answer: 1. 1

Question 15. The chemical reaction shown in the world be accelerated by all of the following processes:

1. Heating A and b together
2. Applying pressure to a and b
3. Adding an appropriate catalyst
4. Increase the conc. Of c.

Answer: 4. Increase the conc. Of c.

Question 16. In most of the metabolic pathways, all needed enzymes are arranged together, in a multienzyme complex within:

1. Solution of atp
2. Membrane
3. Quarternary protein
4. Coenzyme.

Answer: 2. Membrane

Question 17. A non-protein organic part attached firmly to an apoenzyme is called :

1. Cofactor
2. Activator
3. Metallic group
4. Coenzyme.

Answer: 1. Cofactor

Enzyme Catalysis Mcqs For Neet

Question 18. Which is an enzyme that joins two segments of replicated dna?

1. Ligase
2. Lyase
3. Endonuclease
4. None of the above.

Answer: 1. Ligase

Question 19. Apoenzyrne and coenzyme collective produce :

1. Holoenzyme
2. Enzyrne-product complex
3. Cofactor
4. Prosthetic group.

Answer: 1. Holoenzyme

Question 20. Minimum number of amino acids to make an enzyme is:

1. 50
2. 150
3. 500
4. 5000.

Answer: 1. 50

Question 21. Fmn and fad are coenzymes derived from :

1. Ascorbic acid
2. Riboflavin
3. Thiamine
4. Pyridoxine.

Answer: 1. Ascorbic acid

Question 22. Enzymes differ from inorganic catalysts in having:

1. High diffusion rate
2. High-temperature requirement
3. Proteinaceous structure
4. Tendency to become inactivated.

Answer: 3. Proteinaceous structure

Question 23. Active sites of enzymes are composed of :

1. Sugm molecule
2. Metallic ions
3. Organic co-factors
4. Amino acids.

Answer: 4. Amino acids.

Question 24. Pepsin best works at :

1. Ph 7.00
2. Ph 8.5
3. Ph.00
4. Ph 8.00.

Answer: 3. Ph.00

Enzyme Catalysis Mcqs For Neet

Question 25. Of the following chemicals, the one that is classified as an enzyme is :

1. Galactose
2. Lipids
3. Manganese dioxide
4. Protease.

Answer: 4. Protease.

Question 26. Ribozyme is :

1. Rna without sugar
2. Rna with extra phosphate
3. Rna having enzymatic activity
4. All of the above.

Answer: 3. Rna having enzymatic activity

Questions Question 27. Allenzymes:

1. Are amino acids
2. Act best at 60ºc
3. Act best at 7 ph
4. Are proteins.

Answer: 4. Are proteins.

Enzyme Catalysis Mcqs For Neet

Question 28. At high temperatures, the enzyme is :

1. Denaturated
2. Killed
3. Slightly activated
4. Inactivated.

Answer: 1. Denaturated

Question 29. Inorganic catalyst attached to an enzyme is :

1. Apoenzyme
2. Coenzyme
3. Inhibitor
4. Activator.

Answer: 4. Activator.

Question 30. Enzymes are polymers of :

1. Fatty acids
2. Amino acids
3. Hexose sugar
4. Inorganic phosphate.

Answer: 2. Amino acids

Question 31. One is not correct :

1. All enzymes are thermolabile
2. All enzymes are biocatalysts
3. All enzymes are proteins
4. All proteins are enzymes.

Answer: 4. All proteins are enzymes.

Enzymes Mcq For Neet

Question 32. Match the tennis in column 1 with suitable terms in column 2

Which of the following is correct?

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

Answer: 3. 1-G, 2-A, 3-D, 4-F, 5-B, 6-A

Question 33. Modulation:

1. Inhibit enzyme activity
2. Stimulate enzyme activity
3. Function as coenzymes
4. Both 1 and 2.

Answer: 4. Both a and b

Question 34. K. Indicates :

1. Competitive inhibition
2. Denaturation of enzymes
3. Reaction velocity
4. All of these.

Answer: 3. Reaction velocity

Enzymes Mcq For Neet

Question 35. Which is susceptible to feedback inhibition?

1. Zymogen
2. Zymase
3. Glucokinase
4. Hexokinase.

Answer: 4. Hexokinase.

Question 36. Ribozyme was discovered by :

1. Kuhne
2. Because
3. Cech at all
4. Altman at all

Answer: 3. Cech at all.

Question 37. An enzyme that brings about a change in side group without altered composition:

1. Isomerase
2. Epimease
3. Mutase
4. Esterase.

Answer: 3. Mutase

Question 38. Enzymes functional in cells are:

1. Inducible, constitutive, and repressible
2. Inducible and repressible
3. Inducible only
4. Repressible on1y.

Answer: 1. Inducible, constitutive, and repressible

Question 39. Flavoproteins in cellular oxidation are called:

1. Splitting enzyme
2. Redox enzyme
3. Uricolytic enzyme
4. Yellow enzyme.

Answer: 4. Yellow enzyme.

Question 40. The presence of enzymes in the urine is called :

1. Enzymuria
2. Enzymopenia
3. Enzymopathy
4. None of the above.

Answer: 1. Enzymuria

Question 41. Elisa test used in detecting:

1. Antigen
2. Antibody
3. Hormone
4. All of the above.

Answer: 4. All of the above.

Question 42. A person suffering from a.tr.d.s is a resident of an area that is exposed to radio waves which test is preferred to detect h.i.v. Infection.

1. R.i.a (radio immune assay)
2. H.i.v. Test.
3. E.l.i.s.a. Test
4. All of the above.

Answer: 3. E.l.i.s.a. Test

Neet Biology Enzyme Classification Mcqs

Question 43. Which of the following curve profiles show changes in the velocity (v) of an enzyme-catalyzed reactions at different pH values :

Answer: 1. 

Question 44. According to Koshland:

1. The enzyme is never destroyed
2. The enzyme is a rigid molecule
3. The catalytic site of the enzyme is rigid
4. Catalytic sites can be influenced by the presence of substrate.

Answer: 4. Catalytic sites can be influenced by the presence of substrate.

Enzymes MCQ Objective Questions  Question 45. According to Michaelis constant, the value of v is expressed as

1. [Latex]v=\frac{v_{\max } \times(s)}{k_m+(s)}[/latex]
2. [Latex]v=\frac{k_m+(s)}{v_{\max } \times(s)}[/latex]
3. [Latex]\mathrm{v}=\frac{\mathrm{v}_{\max } \times \mathrm{k}_{\mathrm{m}}}{[\mathrm{s}]}[/latex]
4. [Latex]\mathrm{v}=\frac{\mathrm{k}_{\mathrm{m}} \times(\mathrm{s})}{\mathrm{v}_{\max }} .[/Latex]

Answer: 2. [Latex]v=\frac{k_m+(s)}{v_{\max } \times(s)}[/latex]

Question 46. Enzymes catalyzing the hydrolysis of ester and peptide by the addition of water are known as:

1. Transferases
2. Hydrolases
3. Isomerases
4. Oxidation-reduction enzymes.

Answer: 2. Hydrolases

Question 47. Model of fisher implies that;

1. The active site is flexible and adjusts to the substrate
2. The active site requires the removal of PO, group
3. The active site is complementary in shape to that of the substrate
4. None of the above.

Answer: 3. The active site is complementary in shape to that of the substrate.

Question 48. C-amp mediated “cascade model” of enzyme regulation was proposed by :

1. Fisher
2. Sutherland
3. Sumner
4. Koshalnd.

Answer: 2. Sutherland

Question 49. The substrate combines more rapidly with the enzyme when:

1. Km is high
2. Km is low
3. Ki is high
4. Ki is low.

Answer: 2. Km is low

NEET Biology Kingdom Monera Main features

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

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

Read and Learn More NEET Biology Notes

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

Kingdom Monera NEET Notes

NEET Biology Kingdom Monera Bacteria

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

Reproduction

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

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

Kingdom Monera Notes For Neet

Transfer of genetic material (Genetic recombination) 

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

NEET Biology Kingdom Monera Economic Importance Of Bacteria

Cyanobacteria Characteristics NEET

NEET Biology Kingdom Monera Actinomycetes

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

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

Kingdom Monera Notes For Neet

Economic Importance

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

NEET Biology Kingdom Monera Chlamydiae

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

The two species of chlamydiae are:

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

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

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

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

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

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

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

The protoplasm is enclosed by a flexible cell wall.

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

NEET Biology Kingdom Monera Archaebacteria (Ancient Bacteria)

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

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

Differences between cyanobacteria, halophiles, and thermoacidophiles

Gram-Positive vs Gram-Negative Bacteria NEET

Differences between Gran +ve and Gram -ve bacteria

Neet Biology Kingdom Monera

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

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

Cyanobacteria Blue-Green Algae For NEET Biology

Kail V. Non-Nncgcll distinguished blue preen algae from algae. Name k Aihku ten was given by Klilin nml Morris

Blue-Green Algae Main Features

1. Common forms include unicellular, colonial, filamentous, heterotrichous, Gram-variable, and photosynthetic.
2. The cell wall features an external layer that is gelatinous, viscous, and mucilaginous.
3. The cellular contents are partitioned into two regions: the outer chromatograms containing photosynthetic pigments and the inner colorless cytoplasm.
4. The cell wall consists of two layers, with the inner layer composed of peptidoglycan or mucopolysaccharides derived from amino sugars

Example: Glucosamine and amino acids

Example: Muramic acid and diaminopimelic acid

• Bacteria and cyanobacteria lack mitochondria, genuine vacuoles, and endoplasmic reticulum.
• Hormocyst. Thick-walled hormogonia or multicellular akinetes present in cyanobacteria.
• Sterols are nonexistent in both bacteria and cyanobacteria.
• No membrane-bound chloroplasts or photosynthetic lamellae, such as thylakoid arcs, are typically found in the peripheral cytoplasm.
• The authentic nucleus is lacking. Delicate DNA fibrils are either dispersed throughout the cell or concentrated in the central region. Its chromosome is analogous to a bacterial chromosome.
• Cyanobacteria lack distinct reproductive organs, sexual reproduction, and motile reproductive structures.
• Gas vacuoles are frequently found to modulate buoyancy in aquatic environments.
• Cyanobacteria inhabit nearly all aquatic habitats. The organisms inhabit tropical regions, plains, and are found in soil, freshwater, and marine environments.
• They constitute a component of plankton in lakes and oceans. Certain cyanobacteria inhabit the frigid waters of glaciers, while others thrive in hot springs with temperatures exceeding 85°C.
• Certain blue-green algae exist as symbionts with other organisms. For instance, they frequently constitute the algal components of lichens.

Blue Green Algae Notes For Neet

Shapes of Cyanobacteria

Cyanobacteria may be unicellular, colonial, or filamentous. Unicellular forms have single-celled body Examples Synecliococcus, Chroococcus, and Anacystis.

The colonial forms are of two types:

• Dendroid. They are the forms of cyanobacteria in which cells are held together by gelatinous connections example Chamae-siphon.
• Coccoid. They tire unicellular cyanobacteria embedded in a common matrix of mucilage without gelatinous connections, Example Microcystis. Filamentous forms are thread-like multicellular strands in which each filament or strand consists of a sheath of mucilage and one or more cellular strands called trichomes.
• Spirulina has a spirally coiled filament while a branched filament is found in Hapalosiphon.

Filaments that have single trichomes are divided into two types:

1. Homocystous. They have undifferentiated trichomes Example; Oscillatoria and Arthrospira.
2. Heterocystous. They have differentiated trichomes, for Example; Nostoc, and Rivularia.

In Schizothrix more than one trichomes are found in the same sheath of a filament. In Stigonema, a filament may have a few or a multiseriate trichome (in which numerous filaments are associated in a common sheath).

Classification based on morphology, motility, reproduction, and capacity of N2 fixation Cohen Bazire classified cyanobacteria into four groups:

1. Chroococcacean. Examples; Microcystis, Chroococcus, Gloeocapsa, etc.
2. Pseudocapsalean. Example Democarpa
3. Oscillatorian. Example; Oscillatoria.
4. Heterocystous. Examples; Nostoc, Aiiabacita, etc.
5. Among these groups, only Heterocystous has nitrogen-fixing capacity

Cyanobacteria Characteristics And Examples Neet

Economic Importance of Cyanobacteria

1. Useful activities.
   1. Nitrogen fixation is done by about 50 species of cyanobacteria. Based on nitrogen fixation there are two types:
   2. Free-living nitrogen-fixing cyanobacteria, for Example, Anahaeiui, Nostoc, Aulosira, Stylonenui, Stigonema, Oleotricltia, Calotlirix, TolypotlirLx, etc.
   3. They can fix approximately 15-48 kg of nitrogen per hectare per season. Aulosirafertilissima is the most active nitrogen fixer in Rice fields.
   4. Cslindnvpcrmum is an active nitrogen fixer of Sugarcane and Maize fields.
   5. Tolyptthrix is used as a nitrogen fixer in experimental fields. (hi Symbiotic nitrogen-fixing cyanobacteria: Anabaena and Nostoc species are common symbionts in lichens. Anihoceros, Azolla, and Cycas roots in which it can fix nitrogen.
   6. Azolla pinnata has Anabaena azollac in its fronds which is often inoculated to Rice fields for nitrogen fixation.
   7. They provide food for fish and other aquatic animals but Spirulina is regularly collected for human consumption in parts of Africa and India (from Samber Lake of Rajasthani. Nostoc in China, Anabaena in India.
   8. They provide suitable conditions for the growth of other organisms in a hostile environment.
   9. They are used as biofertilizers.
   10. Anabaena and Aulosira do not allow mosquito larvae to grow.
   11. They improve the physical texture of the soil.
2. Harmful activities
   1. Microcystis secretes hydroxylamine which kills aquatic life, birds, and cattle while Anabaena causes gastric trouble in domesticated animals by contaminating the drinking water of these animals.
   2. Microcystis aeruginosa (= Anacystis cyanea), Anabaena flosaquae and Aphanizoinenon flosaquae not only spoil the taste of drinking water but are also toxic to human beings.
   3. They cause depletion of supply to aquatic animals by the formation of blood by Microcystis, Anabaena, and Nostoc.
   4. Anacystis causes corrosion of metallic water pipes.
   5. The growth of algae is controlled by using algicides such as dichlorophen, phylon XI, exalgae, cushion, etc.

Mycoplasma

Cell walls are absent in the simplest and smallest free-living prokaryotes, which are frequently referred to as MLOs (Mycoplasma-like organisms) or PPLOs (Pleuropneumonia-like organisms).

• They are referred to as the “Jokers of the plant kingdom.”Mycoplasma gallispticum is the smallest prokaryote, measuring 0.3 to 0.5 m in size. The following were identified by Roux and Nocard in 1898.
• Nutritionally heterotrophic. Pleuropneumonia is produced in domestic animals, while Witch’s broom is produced in plants.
• Mycoplasma sensitivity. Mycoplasma is a gram-negative bacterium. Penicillin is ineffective against them; however, they are susceptible to other antibiotics, including streptomycin, chloramphenicol, and erythromycin.
• Their resistance to penicillin (and other antibiotics of the same class) may be attributed to the absence of a cell wall.
• This antibiotic disrupts the synthesis of peptidoglycan, a critical component of the bacterial cell wall.
• Reproduction. There is a lack of knowledge regarding mycoplasma reproduction.

However, four types of cellular bodies of Mycoplasma laidlawii have been found. These are:

1. Elementary bodies
2. Secondary bodies
3. Tertiary cell bodies and
4. Quaternary bodies

Elementary bodies reproduce by a process like budding. These grow in size and then again give rise to elementary bodies. In some cases, mycoplasma may reproduce by binary fission. Economic Importance Mycoplasma are always harmful and cause diseases in plants and animals.

Plant diseases. Many plant diseases caused by mycoplasma were earlier considered to be viral diseases before 1967. Since 1967 most of the plant diseases of the yellow group have been reported to be caused by mycoplasma.

These diseases are Little leaf of brinjal Citrus greening Sandal spike Grassy shoot of sugarcane Rice yellow dwarf Colton little leaf or cotton stenosis Sesamum phyllody and several others like Bunty top of papaya Aster yellows.

Neet Previous Year Questions On Cyanobacteria

Potato witch’s

• Pathologies in animals. Mycoplasma is responsible for diseases such as arthritis, various respiratory illnesses, and primary atypical pneumonia (PAP). Mycoplasma liowinis and M.fcrmcntans, among others, are believed to induce infertility in human males.
• In 1909, Howard Taylor Rickets identified novel microbes in the blood of individuals afflicted with Rocky Mountain spotted fever.
• This organism and others of its kind were designated as Rickettsiae, which are today classified as a category of bacteria. The designation Rickettsiae was conferred to pay tribute to the discoverer.

Rickettsiae differ from bacteria in having:

1. Smaller sizes with smaller genomes provide fewer enzymes. Requirement of an exogenous energy supplier for growth.
2. These organisms exist in alternate shapes and hence they are pleomorphic. They have no flagella, pili, capsules, or spores.
3. The cell wall is chemically similar to Gram (-) bacteria, The cytoplasm of Rickettsiae contains both DNA, RNA, and some enzymes.
4. Reproduction is by binary fission. Rickettsial infections usually respond to treatment with tetracyclines or chloramphenicol.

NEET Biology Sense Organs

• Environmental information received by a sense organ is first changed into the language of the nervous system and the process is called transduction.
• Stimuli are perceived by receptors but interpretation of the stimuli is done by specific nervous centres in the brain. Receptors may be exteroreceptors, proprioreceptors or interoreceptors. Exteroreceptors are present in special sense organs like skin, nasal chamber, taste buds, eyes and ears.
• The five kinds of sensory receptors are mechanoreceptors which respond to physical deformations of tissues; chemoreceptors which respond to certain molecules dissolved in solution; thermoreceptors which respond to heat; and painreceptors which respond to excess heat, pressure, or certain chemicals; and electromagnetic which respond to energy of different wavelengths.
• Sensory receptors can also be categorized as exteroreceptors which receive information from the external environment; interoreceptors which receive information from the internal environment; and proprioreceptors which receive information about the body’s orientation in space.
• Skin receptors may be naked free nerve endings or covered bulbs or corpuscles. These may be tango receptors, thermoreceptors, algesia receptors etc.

Read and Learn More NEET Biology Notes

Skeletal Muscle Structure NEET

NEET Biology Sense Of Smell

Olfactoreceptors are present in the olfactory epithelium and are chemoreceptors to specific odours. These show olfactory adaptation as are soon fatigued when exposed to specific odour for a long period.

Evolution Neet Notes

In the case of humans 7 groups of primary odours have been classified :

1. Camphoraceous (Scent of camphor)
2. Musky ( scent of musk )
3. Floral (flowers)
4. Pepperminty ( Scent of oil or peppermint)
5. Ethereal ( Scent of ether)
6. Pungent (Scent of spices)
7. Putrid ( Decaying meat)

NEET Biology Sense Taste Receptors

1. Gustatoreceptors are present in taste buds on the tongue. These are also chemoreceptors. Man can perceive four basic modalities of taste with the help of different taste buds located on different parts of the tongue.
2. Human beings recognise four basic modalities of taste, viz. sweet, sour, salty and bitter. Sweet, sour, salty and bitter tastes are principally perceived at the tip, along the lateral edges, on the upper side of the front half, and the back of the tongue respectively.
3. The taste of food is of vital importance in the process of digestion because taste stimulates reflexes causing secretions of saliva, gastric juice and pancreatic juice.

Rheo Receptors. They are responsible for perceiving water currents. They are of four types.

1. Lateral line sense organs
2. Scattered pit organs
3. Ampulla of Lorenzini
4. Vesicles of Sair
5. Watering of eyes due to gases or smoke is due to irritoreceptors.

Principles Of Inheritance And Variation Neet Notes

NEET Biology Sense The Eye

The eye captures light reflected from objects in the visual field and transforms it into electrical signals, which the brain interprets as visual perception.

• Light is emitted and absorbed in distinct quanta of photons. It propagates as waves of electromagnetic radiation, with wavelengths perceptible to the human eye ranging from 380 to 760 nm, and is most sensitive at 500 nm (i.e., green color).
• Free-living animals require photoreception to identify food, predators, and refuge. Photoreceptors have evolved for this purpose, undergoing progressive improvement over time.
• Planarians (flatworms) possess a “eye cup” that functions as a photosensory organ to perceive light intensity and direction.
• In annelids (polychaetes) and subsequent higher animals, the eye has evolved into a distinct organ.
• In insects and crustaceans, the compound eye consists of individual units known as ommatidia. They are adapted for apposition (mosaic) vision in bright illumination and superposition imagery in low light (darkness).
• It additionally produces colored visuals. Honeybees possess the ability to perceive ultraviolet energy.
• Among all invertebrates, only cephalopods (molluscs) possess eyes with real lenses like to those of vertebrates.

NEET Biology Sense Human (Mammalian) Eye

1. A fluid-filled ball with about 21 mm (17.5 mm just born) metro-posterior diameter (optical or visual avis) lodged in the bony orbit of sphenoid bone with a cushion of fat.
2. It weighs about 7 gin.
3. About 1/6 of the eyeball (l/3rd in frog and 1/5 in rabbit) projects outside while the rest parts remain within the socket. 1 Iris anterior part is covered with transparent cornea.
4. Each eye is protected by upper and lower eyelids with eyelashes.
5. The eyes are somewhat ball-like and are lodged in the deep skull cavities (orbits). The clevis can rapidly close to prevent dust or other things from entering the eyes. The eyelashes also help in this function. On any irritation, due to a fallen particle due to gas or smoke or under certain emotions, the eyes are flooded with a watery secretion or tears.
6. This secretion comes in front of the (car glands, located near the outer border of each eye and it is poured through minute ducts on the inner surface of the upper eyelid. Movements of the upper eyelid spread the secretion over the eye to wash off any dirt.

Structure. The wall of each eye is made of the three concentric layers sclerotic, choroid and retina. In the front, the sclerotic layer forms a transparent, somewhat bulging circular comea.

1. The cornea can be stored and grafted on the other person. The cornea and the rest of the exposed sclerotic layer are covered by another very thin transparent membrane, the conjunctiva, which is the continuation of the inner surface of the eyelids.
2. The pigmented iris, formed by the middle or choroid layer encloses the pupil, visible from outside as a dark window. The iris consists of delicate muscles which regulate the size of the pupil and consequently control the amount of light passing to the retina ciliary body.
3. Just behind the pupil lies a biconvex lens which is held in position by ligaments and muscles. A transparent watery fluid (aqueous humour) fills the narrow space between the lens and the comea. The large chamber behind the lens is filled with a clear, gelatinous substance (vitreous humour).
4. The sensory layer called the retina, consists of two types of cells, rods and cones. The rods are sensitive to dim light and do not distinguish colours, whereas the cone cells are sensitive to bright light and can distinguish colours.
5. The cone cells are most numerous near the back of the eye, opposite the pupil. This part is somewhat depressed and is known as the yellow spot or fovea. Vision is the sharpest here. The sensory fibres from the retina bundle together and emerge from the back of the eyeball as the optic nerve.
6. At the exit of the optic nerve, there are no rods or cones. The part of the image falling at this place is not perceived, and so this place is called the blind spot.

Skeletal Muscle Structure NEET

NEET Biology Sense Associated Glands

1. Lacrimal gland (tear gland).Consists of a chain of three small glands located at the outer angle of each eye. Tear flows into the lacrimal duct through the small pore, and lacrimal punctum to pass into the nasal chamber of its side.

• Tear is a salty fluid, that contains amino acids, glucose and lysozyme.
• A continuous layer of tear is always present upon the comea to keep it moist, and away from dust and other foreign particles. It also nourishes comea and acts as a medium for refraction of light; lysozyme in it is antibacterial.
• In humans tear secretion begins at four months of birth.
• Tearing is stimulated by injury, irritation, emotions etc.

1. The meibomian gland (tarsal gland) is a modified sebaceous gland located on the mar¬gin of eyelids. Its oily secretion makes a film over the tear to prevent it1 fall from the surface of comea.
2. The Zeis gland is also a modified sebaceous gland in the hair follicle of eyelashes to keep them smooth and waterproof by its oily secretion.
3. Glands of Moll are modified sweat glands on the inner surface of eyelids found only in humans, of uncertain function.
4. Harderian Gland. It is a special type of mucous-secreting gland found in aquatic, fossorial and bush dwellers. Mucous keeps the eye moist and protected from abrasion. In frogs it remains beneath the lower eyelid towards the inner corner of the eye, also found in all reptiles and aquatic mammals, rabbits, etc., but absent in man. Its secretion is known as crocodile tears.

Types of Muscles NEET

NEET Biology Sense Refraction Or Focusing

Tear → conjunctiva → cornea → aqueous humor → lens → vitreous humor refract light rays to converge on the retina.

• The cornea exhibits the highest degree of refraction, followed by the lens.
• The lens precisely directs the beam onto the retina to create a picture. Accommodation is achieved by altering the curvature (convexity) of the lens through the action of ciliary muscles, depending on the object’s distance.
• When the ciliary muscle is relaxed, the eye remains at rest and focuses on distant things. To focus on nearby objects, the ciliary muscle contracts to enhance the lens’s convexity.
• The frog possesses inadequate accommodation capabilities; it is hypermetropic in water and myopic on land. Nevertheless, a minor adjustment can be achieved by moving the lens anteriorly and posteriorly, akin to a camera.
• The inverted virtual image is produced on the retina, and normal vision is referred to as emmetropic.
• In humans, each eye possesses a vision field of around 170°. The significant overlap of visual fields aids in assessing the relative positions of objects, constituting depth awareness or stereoscopic vision.
• The typical range of vision in the human eye extends from 30 centimeters to 6 meters.

Evolution Neet Notes

NEET Biology Sense Common Defects Of Eye

1. Myopia (Near-sightedness). When the image of a distant object is focussed in front of the retina due to lengthening of the eyeball or due to increased convexity of the lens. It can be corrected by using appropriate concave lenses.
2. Hypermetropia or Far-sightedness. It is due to just the opposite condition as in myopia. It can be corrected by wearing suitable convex lenses.
3. Astigmatism. It is due to an error in the shape of the lens and cornea, as they are of different curvatures. Cylindrical glasses are used to correct this defect.
4. Presbyopia (old age sight). It is the diminished ability to focus the eye on near objects due to the gradual loss of elasticity of the crystalline lens with age. It can be corrected by use of the convex lens.
5. Cataract. The lens becomes opaque due to different reasons. It can be corrected by removing the lens and replacement by a convex lens by the specialist.
6. Glaucoma. It is an increase in intraocular tension when the pressure within the eye is raised above the normal level (15-20 mm Hg.) If prolonged it brings about blindness.
7. Trachoma. It is caused due to infection by virus conjunctivitis. The cornea may be ulcerated and vision is lost.
8. Squint/ Strabismus/Diplopia  – It is the formation of two images. Corrected surgically.

NEET Biology Muscular System Notes

NEET Biology Sense The Ear

The ear consists of three parts :

1. External
2. Middle
3. Internal ear.

External Ear. The external or the outermost projecting part of the ear is a skin-covered cartilaginous organ called pinna. It collects sound waves and admits them into the tubular auditory passage.

• Some animals can move their external ears in the direction of sound, but such muscles are vestigial in man although some people do have the capacity to move their ears slightly. A waxy layer of cerumen glands in the auditory passage entangles the bacteria and any other minute organisms that may creep in.
• Similarly, the outer openings have fine hair for protection purposes. Somewhat obliquely placed at the inner end of the auditory passage is a delicate blue-grey membrane called the ear drum (tympanum).

Middle Ear. The middle ear consists of a set of three tiny bones, which are lodged in a chamber. The first bone is the hammer-shaped malleus, attached to the inner surface of the car drum (tympanum), by a muscle called tensor tympani.

• Next is the anvil-shaped incus and the third is the stirrup-shaped stapes, the inner end of which is attached to fenestra malls. An air passage of the castellan tube connects the floor of (the middle ear with the pharynx, to balance the air pressure on either side of the tympanum.
• The tympanic cavity opens into the internal ear’s cavity through two apertures – fenestra ovalis and fenestra rotundas.

The car ossicles help in the amplification of sound waves and their transmission to the internal car. These are three in mammals as a characteristic feature :

1. The malleus (hammer) comes first connected to the tympanum, derived from the articular bone of the low er jaw.
2. The incus (anvil) is the second bone upon which the malleus hammers. It is derived from the quadrate bone of the upper jaw.
3. Stapes (stirrup) the last, fork-shaped bone is connected to the membrane of fenestra ovalis. It is derived from oromandibular, a homologous bone, columella auris is the only ear ossicle found in frogs.
4. The middle car is connected with the pharynx through a cartilaginous eustachian tube which gets filled with air and helps maintain equal pressure on both sides of the tympanum.
5. The internal car is very delicate. It has two main regions – the upper utriculus and the lower sacculus. Both are connected by a small and narrow saccule-utricular duct. A small duct, the endolymphatic duct, opens into it; the other end of which opens into a closed endolymphatic sac which is present on the posterior side of the temporal bone.
6. The upper portion i.e. utriculus is connected with three semi-circular canals, which are concerned with the sense of position of the body and not with hearing.
7. From the sacculus arises a long tubular part or cochlea which is coiled like-conch shell and is embedded in a bone of the skull. It carries a system of canals and spaces which are filled with lymph-like fluid and there are fine sensitive membranes running across it.
8. Branches from the auditory nerve enter these membranes. This part is connected with the sense of hearing. The cochlea is attached to the sacculus through ductus reuniens. Cochlea has about 2 coils. The cochlea can be divided into three parts the upper one is scala vestibuli, the middle scala media and the lower one is scala tympani.
9. The upper and lower parts are filled with perilymph whereas the middle one with endolymph. Both the scala vestibule and scala tympani are continuous with each other through a passage called helicotrema.
10. The dorsal wall of scala media is called Reissner’s membrane and the ventral one is the Basilar membrane. Several sensitive structures are found on the basilar membrane like an organ of Corti, cell of deiter, the cells of Hensen and the tectorial membrane.

NEET Biology Muscular System Notes

NEET Biology Sense Equilibrium

• Any alteration in body posture causes the otoliths within the endolymph of the cristae and maculae to contact sensory hairs, generating an impulse that is transmitted to the brain, which then adjusts to maintain balance.
• The cristae in the ampulla of semicircular canals sustain dynamic balance. It is activated when the body is in motion or rotation.
• The maculae in the utriculus and sacculus ensure static balance or orientation of the body or head during a static position (sitting or standing).

NEET Biology Sense Hearing

The process of hearing and its path of sound waves is as follows:

• Sound waves collected by pinna → external auditory meatus→ tympanum →tympanic cavity → ear ossicles (malleus→ incus → stapes) → membrane of fenestra ovalis → perilymph of scala vestibuli →helicotrema →scala tympani (vibrations cause movement of Reissner’s and basilar membranes result in the vibration of endolymph of scala media) → Tectorial membrane →Sensory hair cells of the organ of Corti → Impulse ’ generated → Auditory nerve→ Brain (perception and interpretation of sound vibrations) and sound Is perceived.

Evolution Neet Revision Notes

NEET Biology Sense Organs In Focus

1. Receptors are merely involved in receiving the stimuli and initiating the nerve impulses but cannot interpret the impulses.
2. Interpretation power of nerve impulses lies in the specific sensory areas of the brain,
3. Proprioceptors are maximally present in the sole of feet.
4. Exteroreceptois and proprioceptors are somatic receptors while interoceptors are visceral receptors,  Classification of receptors was given by Sherrington. Reading of a page is an example of exteroception i.e., sensing of the external environment, or Sensing of internal condition and position is inerorecspection.
5. Perception is the conscious awareness and interpretation of sensation.
6. Each eye weighs roughly 7 gins.
7. Photoreceptor cells are present on the innermost layer of the eye. the retina.
8.  The Iris of the eye contains radial bands and rings of circular smooth muscles.
9. The size of the pupil is larger in human females than in males. The Iris of the eye acts as a diaphragm of eye. Iris, being pigmented. gives colour to the eye which depends upon the amount of melanin present example, more melanin in brown eye, less melanin in blue eye but no melanin in albino eye.
10. Rods of the retina have rhodopsin (visual purple) while cones have iodopsin (visual violet), and Rods help in night vision. twilight and Black and white vision, while cones help in day vision and colour vision.
11. There are about 7 million cones in the human eye.
12. Zonula of Zinn is the other name for the suspensory ligament.
13. Monocular vision is found in animals like dogs, rabbits, pigeons, frogs, etc. In this, only one eye is focused on one object at a time.
14. Stereoscopic vision. Binocular vision is Found in most primates and owls among the birds. In this, both eyes can be focused on the same object at the same time.
15. In flatfishes, both eyes are on the right side of the body. Palpebrae. Eyelids. These act as shutters.
16. Meibomian glands are modified oil glands.
17. Glands lying at the edges of eyelids Gland of Zeis and Gland of Moll.
18. Sty Bacterial infection of the gland of Zeis. It is also called
19. hordeolum.
20. Eyelids are absent in cyclostomes, bony fishes and snakes.
21. Plica semilunaris. The third eyelid, also called the nictitating membrane, is vestigial in man.
22. The cornea is non-vascu, a part of the eye. So cornea is most easiest part to transplant as n does not stimulate the immune system.
23. Nutrition to the cornea is provided by alkaline lacrymal secretion. It is differentiated into Bulbar conjunctiva (outside cornea) and palpebral conjunctiva (inner to eyelids). It is a modified stratified epithelium.
24. Owls have a large number of rods and only a few cones in the retina of their eyes.
25. The retina of the fowl’s eye contains only cones.
26. Deer have the biggest eyes in proportion to body size.
27. The region of the environment from which each eye collects light is called the visual field.
28. The normal eye can accommodate light from objects from about 25 cm to infinity.
29. In the ear canal, there are about 4.000 specialized ceruminous glands.
30. The cochlea contains 16.000 and 24.000 hair cells and each hair cell has about 100 hair. They create waves in the lymph fluid of the cochlea and the wave causes the basilar membrane to ripple.
31. The ear acts as a statoacoustic organ that controls hearing and equilibrium.
32. The Pinna of the ear is called the auricle.
33. The pharyngeal opening of the eustachian tube opens during yawning, swallowing and during the ascent or descent of an aeroplane to equalise the pressure inside the tympanic cavity to that outside the eardrum for free vibrations of the eardrum.
34. Audiology. Study of hearing power.
35. Otology. Study of the structure, working and disorders of the ear.
36. Aquatic animals like seals, whales, etc. and monotremes like duck-billed platypi and spiny ant-eaters lack pinna.
37. Thermoreceptors are more in number on the face and hand of man.
38. The most sensitive chemical receptors are the taste and smell receptors.
39. Taste receptors in the tongue respond specifically to sweet, sour, salty and bitter molecules.
40. The nose contains mucus-coated olfactory receptors, over 2 million in number.
41. The mucus produced by Bowman’s gland absorbs odour-iferous substances that stimulate the reception of the cells.
42. The taste of chillies, black pepper and ‘hot’ sauces is not a true sensation. It is a sensation of burning pain produced by the stimulation of pain receptors of the tongue.
43. Many insects such as honey bees, flies, butterflies and moths possess chemoreceptors to taste sensation on their feet.
44. Some mammals such as rhesus monkeys, pigs, cats and dogs possess taste buds for tasting water. But man is deprived of them.

Evolution Neet Chapter Summary

NEET Biology Sense Organs Conclusion

• In fishes, accommodation for near objects is brought about by elongating the eyeball but in other animals, it is brought about by increasing the lens curvature.
• lives, capable of focussing the images of objects possessed by vertebrates and some higher invertebrates like prawns, crabs and insects.
• Prawns, crabs and cockroaches possess compound eyes, each made of many elongated tube-like units called ommatidia. They are crowded over a spherical surface and produce a composite blurred image of the object.
• All animals do not have their olfactory receptors located in the nose. For instance, moths and butterflies possess olfactory chemoreceptors on their antennae.
• The cornea has no vascular or immune systems. Therefore a complete transplant is not rejected by the body and is highly successful.
• Cornea from the eye of a dead person can be stored and transplanted to restore vision in another person. It is so because it is non-vascular and does not stimulate the immune system.
• Owls have the keenest eyesight at night because their eyes have a large number of rods and a few cones in the retina.
• Aquatic mammals like seals, whales, etc., and monotremes like duck-billed platypus and spiny ant eater lack pinna. Tympanum. It is the specialized hearing organ of insects.
• Sea sickness. Tendency of nausea and vomiting due to unusual stimulation of semicircular ducts by the movement
  ment of a ship in the sea.
• The area of the body most sensitive to the sensation of cold is the chest Merkel’s disc is slowly adapting receptors for touch.
• Organ of Ruffini arc the receptors for warmth.
• Cynnolabs. Cone cells are sensitive to blue light radiations.
• Erythrolabs. Cone cells are sensitive to red light radiations.
• Jacobson’s organs. Additional smelling organs of reptiles like Sphenodon, lizards and snakes (best developed). These are also called vomeronasal organs.
• Ampullae of Lorenzini. Thermoreceptors are found in the snout region of fishes.
• A sense of direction is given by the nose.
• Olfactory cells are modified bipolar neurons.
• Grandy’s corpuscles. A special type of Merkel’s corpuscles present in the skin and tongue of birds
• Otoliths/Otoconia. Calcium carbonate crystals
• Harberf s corpuscles. A simple type of Pacinian corpuscles in birds
• Pacinian corpuscles. Vater’s corpuscles and hence Vater Pacinian corpuscles
• Vibration to which the human ear is most sensitive. 1000 cycles /sec
• Harderian glands -Present at an angle of the eye, secrete lubricant for nictitating membrane.
• Eyelids are absent in snakes.

NEET Biology Sense Organ Multiple Choice Questions

Question 1. The Human Retina Can Detect Three Basic Colours. Select The Correct Set Of Colours :

1. Blue, Red And Orange
2. Blue, Red And Yellow
3. Blue, Red And Green
4. Blue, Green And Yellow.

Answer: 3. Blue, Red And Green

Question 2. The Charts Helping To Identify If A Person Is Colour Blind Are :

1. Ishihara’S Charts
2. Reprogram
3. Dichromatic Charts
4. Accommodation Charts.

Answer: 1. Ishihara’s Charts

Question 3. In the Human Eye Maximum Refraction Of Light Takes Place In the:

1. Cornea
2. Aqueous Humour
3. Lens
4. Vitreous Humour.

Answer: 1. Cornea

NEET Important MCQs On Sense Organs

Read and Learn More NEET Biology Multiple Choice Question and Answers

Question 4. Which Part Of The Ear Is Common To Both Frogs And Mammalian Ear?

1. Cochlea
2. Eustachian Tube
3. Organ Of Corti
4. Columella Auris.

Answer: 2. Eustachian Tube

Question 5. Algesireceptors Are Sensitive To :

1. Pressure
2. Coldness
3. Chemicals
4. Pain.

Answer: 4. Pain.

Question 6. How Many Semicircular Canals Are Present In The Ear Of Frog And Man?

1. 3, 2
2. 3, 3
3. 3,1
4. 1, 3.

Answer: 2. 3, 3

Question 7. Colliculi In Eutherians :

1. Are Bigger Than Those In Frog
2. Are Two In Number
3. Concerned With Vision And Audition
4. Concerned With Vision And Maintenance Of Equilibrium.

Answer: 3. Concerned With Vision And Audition

Question 8. The Ends Of Bipolar Neurons In Retina Of Man Touch :

1. Choroid Layer And Ganglion Cells
2. Photosensitive Cells And Ganglion Cells
3. Cornea And Retina
4. Blind Spot And Yellow Spot.

Answer: 2. Photosensitive Cells And Ganglion Cells

NEET Important MCQs On Sense Organs

Question 9. What Will Happen If The Eyes Of A Frog Are Covered With Paper?

1. Frog Will Not Move
2. Frog Will Die Soon
3. Frog Will Move To One Side Only
4. Frog Will Not Do Anything.

Answer: 4. Frog Will Not Do Anything.

Question 10. Which Of These Has the Biggest Eyes In Proportion To Body Size?

1. Horse
2. Camel
3. Elephant
4. Deer.

Answer: 4. Deer

Question 11. The Outer Coat Of Eye Ball Is Known As :

1. Sclerotic
2. Choroid
3. Retina
4. Vascular Ciliary Layer.

Answer: 1. Sclerotic

Question 12. The Middle Coat Of The Eye Ball Is Vascular And Made Up Of:

1. Smooth Muscles
2. Epithelial Cells
3. Circular Muscles
4. Connective Tissue And Black Pigments.

Answer: 4. Connective Tissue And Black Pigments.

Question 13. Iris Is Made Up Of:

1. Rods And Cones
2. Circular And Radial Muscles
3. Glandular Epithelium
4. Adipose Tissue.

Answer: 2. Circular And Radial Muscles

NEET Important MCQs On Sense Organs

Question 14. The Rods Of Retina Are Most Closely Associated With :

1. Blind Spot
2. Colour Vision
3. Bright Light Vision
4. Feeble Light Vision.

Answer: 4. Feeble Light Vision.

Question 15. Rods And Cones In Retina Of Vertebrates Eye Differ In Their Function. Indicate The False Statement:

1. Rods Can Be Stimulated By Low Intensity Of Light While Cones Require High Light Intensity For Stimulation
2. Rods Give A Blurred Image Of An Object While Cones Give Its Sharp Visual Details
3. Rods Give Colour Vision While Cones Give Black And White Perception
4. Both 1 And 3.

Answer: 3. Rods Give Colour Vision While Cones Give Black And White Perception

Question 16. Cavity Of Vitreous Chamber Is :

1. Behind The Lens
2. In Front Of Lens
3. Between Choroid And Retina
4. Between Sclerotic And Choroid.

Answer: 1. Behind The Lens

Question 17. Long Eye Ball Relation To Its Refracting Power Is :

1. Long Sight
2. Myopia
3. Astigmatism
4. Hypermetropia.

Answer: 2. Myopia

Question 18. Visual Purple Is Pigment Concerned With :

1. Colour Of Eye
2. Night Blindness
3. Colour Blindness
4. Perception Of Image In Darkness.

Answer: 4. Perception Of Image In Darkness.

Question 19. Rhodopsin Of Eye Will Require :

1. Mango
2. Carrot
3. Wheat
4. Banana.

Answer: 2. Carrot

Question 20. Iodopsin Is Associated With :

1. Hypophysis
2. Cones
3. Goitre
4. Cretinism.

Answer: 2. Cones

Human Sense Organs NEET MCQs

Question 21. The Vitreous Humour Differs From The Aqueous Humour In:

1. Being Much More Watery
2. Having A Less Refractive Index
3. Being More Viscous
4. Being More Translucent.

Answer: 3. Being More Viscous

Question 22. The Retina Of Vertebrate Eye Consists Of :

1. Rods Only
2. Cones Only
3. Rods And Cones And Neuroglial Cells
4. Rods And Cones.

Answer: 3. Rods And Cones And Neuroglial Cells

Question 23. In Annual Vision Photochemical Sensitivity Of:

1. Carotene Is Used
2. Keratin Is Used
3. Atp Is Used
4. Cuticle Is Used.

Answer: 1. Carotene Is Used

Question 24. Aperture Controlling Light Passage In the Eye Is :

1. Sclerotic
2. Pupil
3. Blind Spot
4. Iris.

Answer: 2. Pupil

Question 25. The Shape Of Lens In The Eye Of Vertebrate Is Altered By :

1. Iris
2. Vitreous Humour
3. Aqueous Humour
4. Ciliary Muscles.

Answer: 4. Ciliary Muscles.

Human Sense Organs NEET MCQs

Question 26. Fovea Centralis In The Human Eye Is Having :

1. Mixture Of Rods And Cones
2. Rods Only
3. Cones Only
4. Nerve Endings Only.

Answer: 3. Cones Only

Question 27. In Vision Light Energy Is :

1. Converted Into Chemical Energy
2. Converted Into Electrical Energy
3. Converted Into Mechanical Energy
4. Converted Into Physical Energy.

Answer: 1. Converted Into Chemical Energy

Question 28. Tapetum Lucidum Layer Is :

1. Jelly-Like
2. Fibrous
3. Crystalline Fibrous
4. Crystalline.

Answer: 4. Crystalline

Questions for NEET Biology Sense Organ Question 29. After Exposure To Bright Light, Some Time Is Needed For Dark Adaptation Because :

1. Rhodopsin Becomes Temporarily Degenerated
2. Rhodopsin Is Bleached By Light And Requires Some Time For Normal Position
3. Rhodopsin Changes To Post-Rhodopsin In Dim Light And This Takes Some Time
4. None Of The Above.

Answer: 1. Rhodopsin Becomes Temporarily Degenerated

Question 30. In Frog’s Eye Sclerotic Is Made Up Of:

1. Bone
2. Muscle And Cartilage
3. Cartilage
4. Fibrous Connective Tissue.

Answer: 4. Fibrous Connective Tissue.

Question 31. The Part Of An Eye Which Acts Like A Diaphragm Of Photographic Camera Is :

1. Pupil
2. Iris
3. Cornea
4. Lens.

Answer: 2. Iris

Human Sense Organs NEET MCQs

Question 32. The Wall Of The Eye Is Made Up Of:

1. Four Main Layers
2. Three Main Layers
3. Thirty Main Layers
4. One Layer Only.

Answer: 2. Three Main Layers

Question 33. Focus In The Vertebrate Eye Is Done By :

1. Iris Muscles
2. Ciliary Muscles
3. Muscles Of Eye Ball
4. Retinal Muscles.

Answer: 2. Ciliary Muscles

Question 34. Tapetum Lucidum  Present :

1. In Retina
2. Cither In Retina Or Clitrfoid
3. In Choroid
4. None Of The Above.

Answer: 2. Cither In Retina Or Clitrfoid

Question 35. Myopia Occurs When The Image or Distant Object Is Focussed :

1. Behind The Retina
2. Above The Retina
3. In Front Of The Retina
4. Below The Retina.

Answer: 3. In Front Of The Retina

Question 36. Astigmatism Is Due To The Irregularities :

1. In The Shape Of Lens And Cornea
2. Of Pigments
3. Of Rods
4. Of Lens.

Answer: 1. In The Shape Of Lens And Cornea

Question 37. Hypermetropia Occurs When The Image Of Near Objects Is Focussed :

1. Above The Retina
2. Upon The Retina
3. Below The Retina
4. Behind The Retina.

Answer: 4. Behind The Retina.

NEET Previous Year Questions On Sense Organs

Question 38. Presbyopia Is Due To The Irregularities :

1. In The Shape Of Lens And Cornea
2. In The Shape Of Lens And Loss Of Its Elasticity
3. In The Shape Of Cornea
4. In The Shape Of Iris.

Answer: 2. In The Shape Of Lens And Loss Of Its Elasticity

Question 39. Night Blindness Is Caused Due To’ The Deficiency Of:

1. Vitamin A
2. Vitamin B
3. Vitamin K
4. Vitamin D.

Answer: 1. Vitamin A

Question 40. Fenestra Vestibuli Amplifies Sound Vibrations By :

1. 2.2 Times
2. 4.5 Times
3. 10 Times
4. 20 Times.

Answer: 1. 2.2 Times

Question 41. Hypoglossal Nerve Is Responsible For The Movement Of Muscles Of:

1. Tongue
2. Ear
3. Eyes
4. Nose

Answer: 1. Tongue

Question 42. Skin Receptors Are Classified Into How Many Categories?

1. Two
2. Five
3. Four
4. Six

Answer: 1. Two

Question 43. The Iris Consists Of Delicate :

1. Ciliary Muscles
2. Roilgh Muscles
3. Soft Muscles
4. Muscles Without Cilia.

Answer: 1. Ciliary Muscles

NEET Previous Year Questions On Sense Organs

Question 44. Short-Sightedness Occurs When The Image Of A Distant Object Is Focussed :

1. On The Back Of The Retina
2. Above The Retina
3. In Front Of The Retina
4. Below The Retina.

Answer: 3. In Front Of The Retina

Question 45. The Function Of Iris Is To :

1. Alter The Size Of Pupil
2. Move The Lens
3. Close The Eyelids
4. Secrete Aqueous Humour.

Answer: 1. Alter The Size Of Pupil

Question 46. Colour Blindness Is :

1. Sex-Linked Genetic Disorder
2. Defect In Lens
3. A Gene Mutation
4. Chromosomal Mutation.

Answer: 1. Sex-Linked Genetic Disorder

Question 47. Colour Blindness Is The Inability To Distinguish Colour Between :

1. Red And Green
2. Red And Yellow
3. Blue And Black
4. Green And Blue.

Answer: 1. Red And Green

Nervous System And Sense Organs NEET Questions

Question 48. The Region Of Clearest Vision In Reina Is Yellow Spot Which Is Known As ;

1. Fovea Vvntiabs
2. Canails Cenlialis
3. Macula Lutea
4. Corpus Luteum.

Answer: 3. Macula Lutea

Sensory Organs MCQ Objective Question  Question 49. Stereoscopic Vision Is Found In :

1. Fish
2. Frog
3. Man
4. Snake.

Answer: 3. Man

Question 50. The Hammer Like Ear Ossicle Is:

1. Malleus
2. Incus
3. Stapes
4. Cochlea.

Answer: 1. Malleus

Question 51. Hat Drum Is Not Responsive To Changes Of:

1. Volume Of Sound
2. Position Of The Body
3. Frequency Of Sound Waves
4. Air Pressure In The Pharynx.

Answer: 2. Position Of The Body

Question 52. Semicircular Canals In Internal Ear Are Concerned With :

1. Balance Of The Body
2. Hearing
3. Intelligence
4. Balance And Hearing.

Answer: 4. Balance And Hearing.

Question 53. Which Of These Is Not An Ossicle Of the Middle Ear Of a Frog?

1. Malleus
2. Columella
3. Stapes
4. None Of These.

Answer: 1. Malleus

Question 54. Eustachian Tube In Case Of Man Connects Ear With :

1. Pharynx
2. Oesophagus
3. Bucco-Pharyngeal Cavity
4. Salivary Duct.

Answer: 1. Pharynx

Question 55. The Sound Reaches The Inner Ear From Ear Drum Through Structures Which Are In A Definite Series. The Series Is :

1. Malleus-Incus-Stapes
2. Columella-Stapes
3. Stapes-Malleus-Incus
4. Malleus-Stapes-Incus.

Answer: 1. Malleus-Incus-Stapes

Nervous System And Sense Organs NEET Questions

Question 56. The Internal Ear Of Vertebrates Is Filled With A Fluid Called :

1. Endolymph
2. Perilymph
3. Haemolymph
4. Lymph.

Answer: 1. Endolymph

Question 57. The Site From Which The Nerve Impulse For Hearing Originates Is :

1. Ear Ossicle
2. Cochlea
3. Tympanum
4. Auditory Nerve.

Answer: 2. Cochlea

Sensory Organs MCQ Objective Question  Question 58. Lateral Line System Helps In :

1. Detecting Water Current
2. Echolocation
3. Thermoregulation
4. All Of The Above.

Answer: 1. Detecting Water Current

Question 59. Otolith Is Formed Of:

1. Calcium Carbonate
2. Calcium Oxalate
3. Magnesium Carbonate
4. Magnesium Sulphate.

Answer: 1. Calcium Carbonate

Question 60. Sensory Patch Of Ampulla Is Called :

1. Cristae
2. Maculae
3. Otoliths
4. Basilar Papilla

Answer: 1. Cristae

NEET Biology Evolution Of Man

Male Primula is positioned to inquire about his origin.

• Male Is classified within the order Primates alongside monkeys and apes.
• The ancestors of humans and other comparable species developed approximately 24 million years ago.

NEET Biology Evolution Of Man Relationship Of Man With Other Primates

The older primate includes three sub-orders. Leinuroidac, Tarsioidac, and Anthropoidae. The Leminoidne and Tarsioidac are collectively called prosimians and Anthropoidae are called simians.

Read and Learn More NEET Biology Notes

• The first mammal was 210 million years old, the first primate 80 million years, the first anthropoid apes 36 million years, and the first hominids 24 million years ago.
• The three families of modern hominids are the Hominidae (the family of man), llylobatidae (Gibbous), and the Pongidne (chimpanzees, gorillas, and orangutans).
• The unique features of the man are erect posture, shorter arms, and a large brain, and can fabricate special tools, use spoken language, and practice prolonged parental care.

• The evolutionary history of man has been built up from the study of fossils and molecular homology.
• Human evolution took place in Africa and Asia.
• A common ancestry for great apes and man has been deduced from similarities in DNA contents, chromosome number, and banding pattern.

NEET Biology Human Evolution Notes

NEET Biology Evolution Of Man Human Evolution

The evolution of man is associated with intelligence and bipedal locomotion

• TA. Huxley (1863)– Book ‘Man’s Place in Nature’ Charle’s Darwin (1971) – ‘Descent of Man’.
• Darwin suggested Man, Apes, and monkeys had a common ancestor.
• Mammals evolved in the early Jurassic period about 210 million years ago from Cynodont Reptiles.

Cotylosaurs → Cynodont → Mammals (Stem reptiles) (reptiles)

Early History

1. Dryopithecus (Proconsul, 18-24 million years)—Common ancestor of humans and apes that lived in Asia as well as Africa. Common species D. africanus. Semi-erect, with hind limbs and forelimbs of the same size.
2. Ramapithecus (Kenyapithecus, 8-15 million years)—It was the earliest man like Primate which probably walked on its legs and possessed dentition similar to humans.
3. Australopithecus (Southern ape, First ape-man, 2-5 million years)—A. africanus was lightly built and omnivorous while weight was 20-30 kg.
   • A. robustus was heavily built and vegetarian, height-120 cm, Cranial capacity-380-430 cm.
   • Face-Prognathous (Projecting Type)—Low forehead, prominent brow ridges, no chin, bipedal locomotion but with bent knees, used crude tools.
4. Homo Habilis (2 Million Years)—Bipedal Locomotion with 150 cm height, (40-50 kg) Cranial capacity 680 cm3, Prominent brow ridges and hominid teeth. He was the first toolmaker. Used chipped stone tools.
5. Homo erects (1.7 Million Years, Erect man)—It walked on erect long legs, 150 cm, cranial capacity 775-1225 cm³, prominent brow ridges, no chin, massive jaws, and longer teeth. Semi-erect posture made more elaborate tools, hunted big game birds, used lire, and primitive speech.
6. Java man (Homo Crectus Credits)—had a smaller cranial capacity (775-900 cm³)— first used fire for cooking and protection.
7. Peking Man (Homo Erectus Pekinesis)—(H. eredus Sinanthropus) had sharp and chisel-shaped tools. Large cranial capacity (915-1225 cm³) Neanderthal Man (Homo sapiens neanderthalcnsis)-30,000-50,000 years ago. 150 cm, Cranial capacity (1300-1600 cm³), sloping forehead, brow ridges, chin, and thick bones of the skull which protruded behind strong shoulders and arms, used tools, and animal hides. Lived in caves and probably built hut-like shelters-had religious feelings and burial customs.
8. Cro-Magnon Man (H. sapiens Fossilis) 20,000-50,000 years back, 180 cm, Cranial capacity-1600 cm³, Broad forehead but arched, brow ridges moderate, strong jaws with man-like dentition, and a well-developed chin. The face was perfectly orthognathous with an arrow and elevated nose. Cave dwellers, the hunter with the domesticated dog, used stone spears and arrowheads, paintings, etc.
9. Modern Man (H. sapiens Sapiens): evolved about 25,000 years ago and spread only about 10,000-11,000 years ago. Cranial capacity- (1400-1450 cm³). Four flexes in the vertebral column, a slight raising of the skull cap.

Time Scale Related To Human Evolution

NEET Biology Evolution Of Man Evolutionary Changes During Human Evolution

1. Skull And Brain. Increase in size, complexity, and intelligence.
2. Bipedal Locomotion. Due to bipedal locomotion forelimbs became free.
3. Forelimbs. Modified into organs of manipulation and lengthening of hindlimbs and shortening of forelimbs.
4. Thumb. Perfection of thumb opposability in forelimbs.
5. Toe. Loss of opposability of great toe in hind limbs.
6. Upright posture. Erect posture by the development of lumbar curve.
7. Jaw. Jaw power reduced.
8. Teeth. Due to omnivorous feed habits, the size of incisors and canines is reduced.
9. Chin. Development of chin.
10. Pelvic Girdle. Development and broadening of iliac bones of the pelvic girdle.
11. Social organization and cultural evolution.

NEET Biology Important Notes PDF

Evolution Of Man

Early Human Evolution

NEET Biology Evolution Of Man Synopsis

Evolutionary History Of Man

1. The evolution of hominids occurred in Africa and Asia.
2. The evolution of man took place in Africa.
3. Dnvpiihecus and Ramapithccus lived about 15 million years ago; they were hairy and walked like apes.
4. 3-4 million years before man-like primates walked in Eastern Africa; they were about 4 feet tall and walked upright.
5. Rcmuipithecus and Sivapithecus lived in Africa and Asia and were the forerunners of hominids.
6. Genus Australopithecus appeared in Africa about 5 million years ago.
7. The genus Homo appeared about 2 million years ago.
8. Homo habilis lived in Africa about 2 million years ago and was characterized by a larger brain; could use tools.
9. Homo credits appeared about 1.7 million years ago and believed to have migrated to Asia and Europe.
10. As a result of the abrupt transition that occurred in Europe about 84000 years ago, Neanderthal man was wiped out and gave way to more efficient Cro-Magnon.
11. Homo sapiens evolved about 10000 years ago.

• Leaky (1930) excavated the first fossil ape Proconsul from early Miocene rocks around Lake Victoria of Kenya. It had 5 cusped molars.
• Leaky (1959) excavated fossils of Zijanthropus (15.5 lakhs year old rocks).
• Leaky (1960) excavated fossils of Homo habilis. (16 to 18 lakhs yrs old).
• Dryopithecus. This fossil ape is known from middle Miocene or early Pliocene rocks
• Sivapithecus was excavated from the middle and late Pliocene rocks of the Shivalik hills of India.
• Fossils Of Ramapithecus And Kenyapithccus were excavated by Lewis (1930) and Leaky (1955) from about 1.2 to 1.4 crore-year-old rocks from Kenya, China, and India.
• Raymond Dart 1924 excavated a fossil baby skull (Tuang baby) from the Pliocene rocks of Australopithecus near Tuang in Africa.
• Robert Brown (1936 onward) excavated fossils of Paranthropus (10-18 yrs old, Pleistocene rocks of Africa).

The most primitive and earliest ape during the Oligocene is called Parapithccus.

• Linnaeus was the first scientist who placed human beings along with monkeys and apes.
• The skull of Pithecanthropus was found in Java.
• Geological evidence for the most primitive numerals found in C. Africa.
• Apes are characterized by the absence of a tail.
• The most primitive ape is Gibbon while the most advanced is Gorilla.
• Old-world Monkeys (Ceboids). Long prehensile (grasping) tails and flat noses, ground dwellers example, Baboons, Rhesus monkeys

New World Monkeys (Ccrcopithecoids) have No such tails but have protruding noses example, spider monkeys, organ grinder’s monkeys (capuchin)

• The first evidence of Australopithecus was the skull of a child discovered by Raymond Dart. Later in 1974 a complete skeleton named Lucy was found by Donald Johanson and Timothy white
• Mitochondrial Eve—A member of archaic Homo sapiens
• The Efe pygmies of Zaicr’s Itwi Forest are among the world’s shortest people, with males reaching an average of 4. 8″ (1,42m) and females reaching 4′ 5″ (1.35 m)
• Piltdown man. It is hypothetical and developed on the basis of artifacts consisting of fragments of skull at Piltdown England

Theories of Human Evolution NEET

Cultural Evolution Is Divided Into Three Phases:

Paleolithic Era. The evolution of knowledge regarding rudimentary hunting implements and primitive language: the human species was Homo habilis.

• Mesolithic Period. Development of intricately designed implements for collective hunting, pyrotechnology, animal skin processing, lithic artistry, and ivory craftsmanship.
• The primary human kinds were Neanderthals and Cro-Magnons.
• Neolithic Period. Progressive development of agriculture, animal domestication, matrimonial practices, education, science, and technology.
• The Indian subcontinent and the Middle East are the initial locations of agriculture. This phase encompassed Homo sapiens.

Percents Of Bands Common Among Humans 

• Chimpanzees: 99 %
• Gorillas: 99%
• Orangutans: 99%
• African Green Monkeys: 95%
• Domestic Cats: 35%
• Mice: 7%

Cranial Capacities

• Chimpanzee (Ape): 400 cc
• Gorilla (Gorilla): 650 cc
• Australopithecus: 300-500 cc
• Java ape Man (Pithecanthropus): 800-1000 cc
• Peking Man (Sinanthropus): 1075 cc
• Neanderthal Man: 1400 cc
• Rhodesian Man: 1280 cc
• Cromagnon Man: 1600 cc
• Modern Man (Homo sapiens): 1900-1450 cc

NEET Biology Evolution Of Man Multiple Choice Questions And Answers

Question 1. First Homonids are:

1. Ramapithecus
2. Kcnyapithccus
3. Both 1 and 2
4. Australopithecus.

Answer: 3. Both 1 and 2

Question 2. Who was the first civilized man?

1. Cro-Magnon min
2. Neanderthal man
3. Hcidelbcrgs man
4. Temifier man.

Answer: 2. Neanderthal man

Question 3. The first human fossil probably belonged to:

1. Zizanthropus
2. Australopithecus
3. Pleisanthropus
4. Pilhicanthropus.

Answer: 2. Australopithecus

Read and Learn More NEET Biology Multiple Choice Question and Answers

Evolution NEET Practice Questions MCQs Question 4. The age of mammals is known as:

1. Cenozoic
2. Mesozoic
3. Palaeozoic
4. Psychozoic.

Answer: 1. Coenozoic

Question 5. The direct ancestral race of modern man was possibly:

1. Cromagnon man
2. Peking man
3. Neanderthal man
4. Java man.

Answer: 1. Cromagnon man

Question 6. Which of the following is not in the direction of the evolution of the human species?

1. Raised orbital ridges
2. Binocular vision
3. Opposable thumb
4. Developed brain.

Answer: 1. Raised orbital ridges

Question 7. Which one of the following eras in the geological time scale corresponds to the Person when life has not originated upon earth?

1. Palaeozoic
2. Mesozoic
3. Cenozoic
4. Azoic.

Answer: 4. Azoic

Question 8. Among the primates listed below which one is the closest relative of modern man:

1. Gorilla
2. Sinanthropus
3. Gibbon
4. Orangutan.

Answer: 2. Sinanthropus

Question 9. The Java man is considered to have existed in:

1. Java only
2. China only
3. Africa
4. Java, China, and Africa.

Answer: 4. Java, China, and Africa.

Question 10. Neanderthal man:

1. Resembles modem man
2. Was less advanced than modern man
3. Had a larger brain than modern man
4. Had a much smaller brain than modern man.

Answer: 3. Had a larger brain than modern man

Human Evolution NEET Questions

Question 11. The ancestor of the man who first stood erect was:

1. Java man
2. Australopithecus
3. Peking man
4. Cro-magnon.

Answer: 2. Australopithecus

Question 12. Which of (lie following is true for Homo sapiens?

1. Protruded mouth
2. Cranial capacity 1450 cc
3. Canine absent
4. Jail present.

Answer: 2. Cranial capacity 1450 cc

Question 13. The skull of Pithecanthropus erectus was found in:

1. Africa
2. Java
3. America
4. All of the above.

Answer: 2. Java

Question 14. The pre-historic ancestor of man which existed during the Pleistocene era is:

1. Australopithecus
2. Zinjanthropus
3. Neanderthal man
4. Atlantic man.

Answer: 3. Neanderthal man

Question 15. The most recent fossil is of:

1. Cromagnon man
2. Java man
3. African man
4. Peking man.

Answer: 1. Cromagnon man

Question 16. The name of the fossil man of Shivalik Hills is:

1. Australopithecus
2. Dryopithecus
3. Sivapithecus
4. Ramapithecus.

Answer: 4. Ramapithecus.

Question 17. The recent ancestors of modern man were:

1. Java ape man and Peking man
2. Peking and Rhodesian man
3. Rhodesian man and Cromagnon man
4. Cromagnon man and Neanderthal man.

Answer: 4. Cromagnon man and Neanderthal man

Human Evolution NEET Questions

Question 18. Homo erectus is the zoological name of:

1. Java ape man
2. Peking man
3. Neanderthal man
4. Nutcracker man.

Answer: 1. Java ape man

Question 19. The earliest site where human civilization and crop cultivation started was presumably:

1. Around the Caspian and Mediterranean Sea
2. Around river Nile
3. Chinese river Nile
4. All of the above.

Answer: 1. Around the Caspian and Mediterranean Sea

Question 20. Cromagnon man was:

1. Herbivorous
2. Frugivorous
3. Sanguivorous
4. Carnivorous.

Answer: 4. Carnivorous.

Question 21. Which one of the fossil men stood first?

1. Australopithecus
2. Homo erectus
3. Sinanthropus
4. Gigantopithccus.

Answer: 1. Australopithecus

Question 22. Neanderthal man differs from modern man in the:

1. Receding jaw
2. Protruding jaw
3. Can make good tools
4. Having a stockier body.

Answer: 4. Having a stockier body.

NEET Biology Evolution MCQs

Question 23. Which of these is considered a trend in primate evolution?

1. Development of non-prehensile tail
2. Development of monocular vision
3. Decreased dependence on smell
4. Elimination of clavicle.

Answer: 3. Decreased dependence on smell

Question 24. Which primate existed in the first half of the Eocene epoch (53-58 million years ago)?

1. Prosinnans
2. Prosimians and monkeys
3. Prosimians, monkeys, and apes
4. Prosimians, monkeys, apes and hominids.

Answer: 1. Prosinnans

Question 25. Which of these prosimians are now found only on the island of Madagascar?

1. Lxuinir
2. Loris
3. Galago
4. Bush baby.

Answer: 1. Lxuinir

Question 26. The immortality of soul hypothesis has given rise to the discovery of:

1. Heidelbergensis man
2. Temifier man
3. Ncanderthalensix
4. Homo sapiens.

Answer: 3. Ncanderthalensix

NEET Biology Evolution MCQs

Question 27. The present age is known as:

1. Bronze age
2. Iron age
3. Silver age
4. Golden age.

Answer: 2. Iron age

Question 28. Who discovered the use of the weapon and tools first?

1. Homo hails
2. Handyman
3. Both 1 and 2
4. Homo erectus

Answer: 3. Both 1 and 2

Question 29. Cannibalism is local in:

1. Java man
2. Peking man
3. Cromagnon man
4. Both (1) and (2).

Answer: 4. Both (1) and (2).

Question 30. The cranial capacity of Java ape-man was about:

1. 560 cc
2. 900 cc
3. 1300 cc
4. 1600 cc.

Answer: 2. 900 cc

Biology MCQ Origin and Evolution of Man Question 31. The first fossil of an African ape-man was discovered by:

1. Dr. Leaky
2. E.Dubois
3. Artlicr Keith
4. Raymond Dart.

Answer: 4. Raymond Dart.

Question 32. Peking man is known as:

1. Australopithecus
2. Sinanthropus
3. Pithecanthropus
4. Homo sapiens.

Answer: 2. Sinanthropus

Question 33. Which of the fossil men given below was an expert in making tools, weapons, paintings, etc?

1. Java ape-man
2. Peking man
3. African man
4. Cro-magnon man

Answer: 4. Cro-magnon man

Question 34. The cranial capacity was the largest in one of the following fossils of man:

1. Java ape-man
2. Cromagnon man
3. Neanderthal man
4. Peking man.

Answer: 2. Cromagnon man

NEET Biology Chapter-wise MCQs

Question 35. Continents where most of the primitive men have been discovered:

1. Africa
2. Asia
3. America
4. Australia.

Answer: 1. Africa

Question 36. Which of the following factors is considered best in the evolution of man?

1. Extinction of Reptiles
2. Appearance of Angiospenns
3. Preference for cave life
4. Pleistocene climate.

Answer: 4. Pleistocene climate.

Question 37. Pithecanthropus erectus fossil was found in:

1. China
2. Japan
3. Java
4. Texas.

Answer: 3. Java

Question 38. The cranial capacity is nearly 1000 cc of:

1. Java man
2. Neanderthal man
3. Peking man
4. Cromagnon man.

Answer: 1. Java man

Question 39. The man who used stones for the first time was:

1. Cromagnon
2. Neanderthal man
3. Homo erectus
4. Homo habilis.

Answer: 4. Homo habilis.

NEET Biology Chapter-wise MCQs

Question 40. Which of the following is not a characteristic of apes?

1. Movement in the trees by brachiation
2. Movement on the ground by knuckle-walking
3. A wrist that bends backward
4. Highly mobile shoulder joints.

Answer: 3. Wrist that bends backward

NEET Biology Evolution Of Life MCQ Question Bank Question 41. Which of the following is not an anatomical change from ape to Homo sapiens?

1. From locking to non-locking knee joints
2. From a long, thin pelvis to a bowl-like pelvis
3. From opposable thumb to non-opposable thumb
4. From flat to arched feet.

Answer: 1. From locking to non-locking knee joints

Question 42. Tuang Baby is the name of:

1. Australopithecus
2. A. Africanus
3. A. afarensis
4. A. bosei.

Answer: 2. A. Africanus

Question 43. Early True Man was:

1. Peking Man
2. Java Man
3. Neanderthal Man
4. Homo habilis.

Answer: 4. Homo habilis.

Question 44. The dog was domesticated by:

1. Homo sapiens neanderthalensis
2. Homo sapiens fossilis
3. Homo heidelbergensis
4. Homo sapiens sapiens.

Answer: 3. Homo heidelbergensis

Question 45. The name of Mio-Pliocene apes is:

1. Dryopithecus
2. Paranthropus
3. Australopithecus
4. Ramapithecus.

Answer: 1. Dryopithecus

NEET Evolution Questions with Answers

Question 46. The maximum size of a modem brain is:

1. 2000 cc
2. 100 cc
3. 1500 cc
4. 2200 cc.

Answer: 3. 1500 cc

Question 47. The name of the earliest human ancestor from India is:

1. Paranthoropus
2. Ramapithecus
3. Australopithecus
4. Dryopithecus.

Answer: 2. Ramapithecus

Question 48. The latest ancestral race of modern man was possibly:

1. Java man
2. Peking man
3. Neanderthal man
4. Cromagnon man.

Answer: 4. Cromagnon man.

Question 49. “Peking Man” was:

1. Australopithecus
2. Sinanthropus
3. Zinjanthropus
4. None of the above.

Answer: 2. Sinanthropus

Question 50. Which of the following is not correct?

1. About 15 mya, primates called Dryopithecus and Ramapithecus appeared.
2. Homo erectus had a large brain around 900 cm³.
3. The brain capacities were between 650 to 800 cm³ of Homo habilis.
4. Ramapithecus was more ape-like.

Answer: 4. Ramapithecus was more ape-like

NEET Evolution Questions with Answers

Question 51. Dryopithecus was:

1. Early human
2. Human ancestor
3. Ape ancestor
4. Ancestors of both apes and humans

Answer: 4. Ancestor of both apes and humans

Question 52. The earliest man-like primate was:

1. Ramapithecus
2. Australopithecus
3. Homo habilis
4. Homo erectus.

Answer: 1. Ramapithecus

Question 53. The first human fossil belonged to:

1. Zinjanthropus
2. Australopithecus
3. Cromagnon man
4. Homo neanderthalensis.

Answer: 2. Australopithecus

Question 54. Fossils of so-called ‘Java Man’ and ‘Peking Man’ belong to:

1. Homo sapiens
2. Homo erectus
3. Homo habilis
4. None of these.

Answer: 2. Homo erectus

NEET Evolution Questions with Answers

Question 55. Anthropoid apes were ancestors of:

1. Monkeys
2. Apes
3. Homo habilis
4. All the apes.

Answer: 1. Monkeys

Origin and Evolution of Man MCQ Question 56. The brain of Australopithecus measured:

1. 350-450 cm³
2. 1400-1450 cm3³
3. 700-900 cm³
4. 800-1400 cm³

Answer: 1. 350-450 cm³

Question 57. Possession of child-like traits by an adult man is called:

1. Gerontomorphism
2. Orthogenomorphism
3. Pedomorphism
4. Foetomorphism.

Answer: 3. Pedomorphism

Question 58. The ancestor of the man who first stood erect was:

1. Australopithecus
2. Java ape man
3. Peking man
4. Cromagnon.

Answer: 1. Australopithecus

Question 59. Cro-magnon was:

1. Carnivorous
2. Omnivorous
3. Herbivorous
4. Frugivorous.

Answer: 1. Carnivorous

Question 60. The first fossils of prehistoric man were discovered by:

1. E. Lewis
2. Raymond Dart
3. Leaky
4. Eugene Dubois.

Answer: 1. E. Lewis

Question 61. Colored rock paintings were presumably first made by:

1. Cromagnon man
2. Neanderthal man
3. Java ape man
4. Peking man.

Answer: 1. Cromagnon man

Question 62. The earliest man who used tools was:

1. Homo habilis
2. Homo erectus
3. Java man
4. Peking man.

Answer: 1. Homo habilis

Human Evolution NEET Questions

Question 63. The characteristics of modern man are:

1. Small teeth without huge canines and slight curvature of the vertebral column
2. A flattened face without muzzle and brow ridges
3. Rounded skull with downward-looking foramen magnum
4. All of these

Answer: 1. Small teeth without huge canines and slight curvature of the vertebral column

Question 64. The first evidence of the ceremonial burial of the dead has been found with fossils of

1. Cromagnon man
2. Java ape man
3. Nemuleillial man
4. Peking man.

Answer: 1. Cromagnon man

Question 65. Loss of pigmentation, slender body, reduced appendages, and absence of visual organs are adaptations in:

1. Cave animals
2. Aquatic animals
3. Ailmreal animals
4. Burrowing animals

Answer: 1. Cave animals

Evolution NEET Practice Questions MCQs Question 66. Modem man, Homo sapiens sapiens began spreading all over the globe some:

1. 10000 years ago
2. 150000 years ago
3. 20000 years ago
4. 25000 years ago

Answer: 1. 10000 years ago

Question 67. According to the geological chronology, man belongs to which era

1. Mesozoic
2. Palaeozoic
3. Piepalaeozoic
4. Coenozoic.

Answer: 4. Coenozoic.

Question 68. “Piltdown man” was:

1. Earlier specimens of fossil bones of a man found in Pilldown
2. Skull of Neanderthal man found in Germany
3. Skull and leg bones of Australopithecus
4. A fake assemblage of bones of the skull.

Answer: 4. A fake assemblage of bones of the skull.

Question 69. A pertinent example where die study of human trials has helped in understanding evolution is:

1. Congenital diseases
2. Eye colour
3. Blood groups
4. Chromosomal variations.

Answer: 3. Blood groups

Question 70. DNA matching has shown human beings to be nearest to:

1. Chimpanzee
2. Gorilla
3. Gibbon
4. Rhesus Monkey.

Answer: 1. Chimpanzee

Question 71. Orthognalhotis face occurs in:

1. Homo sapiens
2. Gorilla
3. Ramapilhecus
4. Homo habilis

Answer: 1. Homo sapiens

Human Evolution NEET Questions

Question 72. Simian gap is;

1. Distance between two nostrils
2. Small diastema
3. The gap between nostrils and upper lip
4. None of the above.

Answer: 2. Small diastema

Question 73. Which of the following primates is the closest relative to modern man

1. Orangutan
2. Sinanthropus
3. Gibbon
4. Gorilla.

Answer: 2. Sinanthropus

Question 74. The earliest man-like primate and oldest of man’s ancestors which is in direct line with human evolution is:

1. Oreopilhecus
2. Proconsul africanus
3. Ramapilhecus
4. Australopithecus.

Answer: 2. Proconsul africanus

Question 75. The fossil of the first known ape is:

1. Dryopilhccus
2. Oreopilhecus
3. Propliopithecus
4. Ramapilhecus.

Answer: 3. Propliopithecus

Question 76. Which of the following is the fossil of the first man-ape

1. Australopithecus
2. Ramapilhecus
3. Homo credits
4. Peking man.

Answer: 1. Australopithecus

Evolution NEET Practice Questions MCQs Question 77. Who said that the human body is a walking museum of antiquities

1. Wejsmann
2. Wiedersheim
3. Wollman
4. Wilkins.

Answer: 2. Wiedersheim

Question 78. Who wrote the first book on human origin

1. Aristotle
2. Linnaeus
3. Huxley
4. Darwin.

Answer: 3. Huxley

Human Evolution NEET Questions

Question 79. Outwardly directed widely separated nostrils occur in:

1. Gorilla
2. New World Monkeys
3. Loris
4. Apes.

Answer: 2. New World Monkeys

Question 80. The fire was first used for protection and cooking by:

1. Java man
2. Neanderthal man
3. Peking man
4. Cromagnon.

Answer: 2. Neanderthal man

Question 81. The features not in the direction of the evolution of the human species are:

1. Raised orbital ridges
2. Binocular vision
3. Opposable thumb
4. None of the above.

Answer: 1. Raised orbital ridges

NEET Biology Evolution MCQs

Question 82. In gorillas, great apes, and chimpanzees, the number of chromosomes is:

1. 2N = 46
2. 2N = 44
3. 2N = 48
4. None of these.

Answer: 3. 2N = 48

Question 83. Dryopilhccus occurred:

1. 50 million years ago
2. 50 billion years ago
3. 24 billion years ago
4. 24 million years ago.

Answer: 4. 24 million years ago.

Question 84. What is the brain size of a man?

1. 350-450 cm³
2. 850-950 cm³
3. 1400-1450 cm³
4. 1800-1850 cm³

Answer: 3. 1400-1450 cm³

Question 85. Dubois in 1891 found the fossil of Java ape man. It is:

1. Sinanthropus pekinensis
2. Pithecanthropus erectus
3. Homo rhodesincsis
4. Homo sapiens.

Answer: 2. Pithecanthropus erectus

Question 86. The smallest cranial capacity is that of the:

1. Modern man
2. Cromagnon man
3. Neanderthal man
4. Java man.

Answer: 4. Java man.

Question 87. The smallest cranial capacity is that of the:

1. Modern man
2. Cro-magnon man
3. Neanderthal man
4. Java man.

Answer: 4. Java man.

Question 88. Cranial capacity was highest in:

1. Java man
2. Cromagnon
3. Neanderthal man
4. Peking man.

Answer: 2. Cromagnon

NEET Biology Evolution MCQs

Question 89. Which of the following fossil man possessed a cranial capacity almost equal to that of modern man

1. Neanderthal man
2. Java ape man
3. Peking man
4. Australopithecus alricans.

Answer: 1. Neanderthal man

Question 90. Match the following lists and give the correct answer from the code given below the lists.

Answer: 2

Question 91. Which of the following is correct?

1. Australopithecus is the real ancestor of modern man
2. Cromagnon man’s fossil has been found in Ethiopia
3. Homo erectus is the ancestor of man
4. Neanderthal man is the direct ancestor of Homo sapiens.

Answer: 3. Homo erectus is the ancestor of man

Question 92. The age of the fossil of Dryopithecus on the geological time scale is:

1. 75 x 10⁶ years back
2. 2.5 x 10⁶ years back
3. 25 x 10⁶ years back
4. 50 x 10⁶ years back.

Answer: 3. 25 x 10⁶ years back

Question 93. The extinct human who lived 1,00,000 to 40,000 years ago, in Europe. Asia and parts of Africa, with short stature, heavy eyebrows, retreating foreheads, large jaws with heavy teeth, stocky bodies, a lumbering gait, and stooped posture were:

1. Neanderthal human
2. Cro-Magnan humans
3. Ramapithecus
4. Homo habilis.

Answer: 1. Neanderthal human

Question 94. Homo sapiens evolved during

1. Pleistocene
2. Oligocene
3. Pliocene
4. Miocene

Answer: 1. Pleistocene

Question 95. Which of the following is the closest relative of man?

1. Chimpanzee
2. Gorilla
3. Orangutan
4. Gibbon

Answer: 1. Chimpanzee

Question 96. Which of the following is the correct order of the evolutionary history of man?

1. Peking man. Homo sapiens, Neanderthel man, Cromagnon man
2. Peking man. Neanderthal man, Homo sapiens, Cromagnon man
3. Peking man, Hedalberg man, Neanderthal man, Cromagnon man
4. Peking man, Neanderthal man, Homo sapiens, Hedalberg man

Answer: 3. Peking man, Hedalberg man, Neanderthal man, Cromagnon man

Question 97. In recent years, DNA sequences of mt-DNA and Y-chromosomes were considered for the study of human evolution, because they:

1. Can be studied from the samples of fossil remains
2. Are small and thus easy to study
3. Are uniparental in origin and do not take part in recombination.
4. Their structure is known in greater detail.

Answer: 2. Are small and thus easy to study

Question 98. Which of the following was the transitional stage between apes and humans:

1. Homo habilis
2. Homo erectus
3. Australopithecus ramidus
4. Australopithecus Africans.

Answer: 3. Australopithecus ramidus

Question 99. Highest cranial capacity is found in:

1. Homo sapiens sapiens
2. Neanderthal man
3. Peking man
4. Cro-magnon man.

Answer: 4. Cro-magnon man.

Question 100. Cromagnon man was:

1. Frugivorous
2. Carnivorous
3. Herbivorous
4. Omnivorous.

Answer: 2. Carnivorous