NEET Biology Principles of Inheritance and Variation MCQs Set C

Question: The variation/difference in the offsprings of a species from their parents constitutes an important component of

• a) Genetics
• b) Speciation
• c) Species fixation
• d) Heredity

Answer: Genetics

Question: If two pea plants having red (dominant) coloured flowers with unknown genotypes are crossed, 75% of the flowers are red and 25% are white. The genotypic constitution of the parents having red coloured flowers will be

• a) Both heterozygous
• b) Both homozygous
• c) One homozygous and other heterozygous
• d) Both hemizygous

Answer: Both heterozygous

Question: Walter Sutton is famous for his contribution to

• a) Chromosomal theory of inheritance
• b) Totipotency
• c) Genetic engineering
• d) Quantitative genetics

Answer: Chromosomal theory of inheritance

Question: A polygenic trait is controlled by 3 genes A, B and C. In a cross AaBbCc × AaBbCc, the phenotypic ratio of the offsprings was observed as

1 : 6 : x : 20 : x : 6 : 1
What is the possible value of x?

• a) 15
• b) 25
• c) 9
• d) 3

Answer: 15

Question: The chromosome constitution 2n – 2 of an organism represents

• a) Nullisomic
• b) Haploid
• c) Monosomic
• d) Trisomic

Answer:  Nullisomic

Question: Mendel's principle of segregation means that the germ cells always receive

• a) One of the paired alleles
• b) One pair of alleles
• c) One quarter of the genes
• d) Any pair of alleles

Answer: One of the paired alleles

Question: Absence of one sex chromosome causes

• a) Turner's syndrome
• b) Klinefelter's syndrome
• c) Down's syndrome
• d) Tay-Sach's syndrome

Answer: Turner's syndrome

Question: Chimera is produced due to

• a) Somatic mutations
• b) Lethal mutations
• c) Reverse Mutations
• d) Pleiotropic mutations

Answer: Somatic mutations

Question: Haploids are more suitable for mutation studies than the diploids. This is because

• a) All mutations, whether dominant or recessive are expressed in haploids
• b) Mutagens penetrate in haploids more effectively than diploids
• c) Haploids are reproductively more stable than diploids
• d) Haploids are more abundant in nature than diploids

Answer: All mutations, whether dominant or recessive are expressed in haploids

Question: Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/ linkage?

• a) Klinefelter’s syndrome – 44 autosomes + XXY
• b) Erythroblastosis foetalis – X-linked
• c) Down’s syndrome – 44 autosomes + XO
• d) Colour blindness – Y-linked

Answer: Klinefelter’s syndrome – 44 autosomes + XXY

Question: The genes, which remain confined to differential region of Y-chromosome, are

• a) Holandric genes
• b) Mutant genes
• c) Autosomal genes
• d) Completely sex-linked genes

Answer: Holandric genes

Question: The colour blindness is more likely to occur in males than in females because

• a) Genes for characters are located on the X-chromosomes
• b) The Y-chromosome of males have the genes for distinguishing colours
• c) The trait is dominant in males and recessive in females
• d) None of these

Answer:  Genes for characters are located on the X-chromosomes

Question: Albinism is a congenital disorder resulting from the lack of the enzyme

• a) Tyrosinase
• b) Xanthine oxidase
• c) Catalase
• d) Fructokinase

Answer: Tyrosinase

Question: An abnormal human male phenotype involving an extra Y-chromosome (XYY) is a case of

• a) Jacob syndrome
• b) Intersex
• c) Down’s syndrome
• d) Edward’s syndrome

Answer: Jacob syndrome

Question: The phenomenon, in which an allele of one gene suppresses the activity of an allele of another gene, is known as

• a) Epistasis
• b) Dominance
• c) Suppression
• d) Inactivation

Answer: Epistasis

Question: Barr body in mammals represents

• a) One of the two X-chromosomes in somatic cells of females
• b) All the heterochromatin in female cells
• c) The Y-chromosome in somatic cells of male
• d) All the heterochromatin in male and female cells

Answer: One of the two X-chromosomes in somatic cells of females

Question: When two dominant independently assorting genes react with each other producing effect jointly they are called

• a) Complementary genes
• b) Supplementary genes
• c) Collaborative genes
• d) Duplicate genes

Answer: Complementary genes

Question: A genetically diseased father (male) marries with a normal female and gives birth to 3 carrier girls and 5 normal sons. It may be which type of genetical disease?

• a) Sex-linked disease
• b) Sex-influenced disease
• c) Blood group inheritance disease
• d) Sex-limited disease

Answer: Sex-linked disease

Question: A person whose father is colour blind marries a lady whose mother is daughter of a colour blind man. Their children will be

• a) All daughter normal
• b) All sons and daughters colour blind
• c) Some sons normal and some daughters colour blind
• d) All sons colour blind

Answer: All daughter normal

Question: In which of the following disease, the individual has one less X-chromosome?

• a) Turner’s syndrome
• b) Bleeder’s disease
• c) Klinefelter’s syndrome
• d) Down’s syndrome

Answer: Turner’s syndrome

Question: H.J. Muller had received Nobel Prize for

• a) Discovering the induced mutations by X-rays
• b) Proving that the DNA is a genetic material
• c) His studies on Drosophila for genetic study
• d) Discovering the linkage of genes

Answer: Discovering the induced mutations by X-rays

Question: The polygenic genes show

• a) Different phenotypes
• b) None of these
• c) Different genotypes
• d) Different karyotypes

Answer: Different phenotypes

Question: A person whose father is colour blind marries a lady whose mother is daughter of a colour blind man. Their children will be

• a) All daughter normal
• b) All sons and daughters colour blind
• c) Some sons normal and some daughters colour blind
• d) All sons colour blind

Answer: All daughter normal

Question: H.J. Muller had received Nobel Prize for

• a) Discovering the induced mutations by X-rays
• b) Proving that the DNA is a genetic material
• c) His studies on Drosophila for genetic study
• d) Discovering the linkage of genes

Answer: Discovering the induced mutations by X-rays

Question: In which of the following disease, the individual has one less X-chromosome?

• a) Turner’s syndrome
• b) Bleeder’s disease
• c) Klinefelter’s syndrome
• d) Down’s syndrome

Answer: Turner’s syndrome

Question: Foetal sex can be determined by examining cells from the amniotic fluid by looking for

• a) Barr bodies
• b) Autosomes
• c) Kinetochore
• d) Chiasmata

Answer: Barr bodies

Question: A fruit fly is hemizygous for sex-linked genes, mated with normal female fruit fly, the males specific chromosome will enter egg cell in the proportion

• a) 1 : 1
• b) 2 : 1
• c) 7 : 1
• d) 3 : 1

Answer: 1 : 1

Question: Genetic identity of a human male is determined by

• a) Sex-chromosome
• b) Cell organelles
• c) Autosome
• d) Nucleolous

Answer: Sex-chromosome

Question: Different forms of a gene located at the same locus of chromosomes are called

• a) Multiple alleles
• b) Polygenes
• c) Oncogenes
• d) None of these

Answer: Multiple alleles

Question: After crossing two plants, the progenies are found to be male sterile. This phenomenon is found to be maternally inherited and is due to some genes which reside in

• a) Mitochondria
• b) Cytoplasm
• c) Nucleus
• d) Chloroplast

Answer: Mitochondria

Question: Albinism is known to be due to an autosomal recessive mutation. The first child of a couple with normal skin pigmentation was an albino. What is the probability that their second child will also be an albino?

• a) 25%
• b) 100%
• c) 75%
• d) 50%

Answer: 25%

Question: How many different types of genetically different gametes will be produced by a heterozygous plant having the genotype AABbCc?

• a) Four
• b) Two
• c) Nine
• d) Six

Answer: Four

Question: When a single gene influences more than one traits it is called

• a) Pleiotropic
• b) Epistasis
• c) Pseudodominance
• d) None of these

Answer: Pleiotropic

More Questions...............................

Question: Mental retardation in man, associated with sex chromosomal abnormality is usually due to

• a) Increase in X complement
• b) Large increase in Y complement
• c) Moderate increase in Y complement
• d) Reduction in X complement

Answer: Increase in X complement

Question: Loss of a X-chromosome in a particular cell, during its development, results into

• a) Gynandromorphs
• b) Meta female
• c) Triploid individual
• d) Myotonic dystrophy

Answer: Gynandromorphs

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

• a) He would not have discovered the law of independent assortment
• b) He would have discovered sex linkage
• c) He could have mapped the chromosome
• d) He would have discovered blending or incomplete dominance

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

Question: A woman with two genes for haemophilia and one gene for colour blindness on one of the ‘X’ chromosomes marries a normal man. How will the progeny be?

• a) 50% haemophilic colour-blind sons and 50% haemophilic sons
• b) 50% haemophilic daughters and 50% colour blind daughters
• c) All sons and daughters haemophilic and colour-blind
• d) Haemophilic and colour-blind daughters

Answer: 50% haemophilic colour-blind sons and 50% haemophilic sons

Question: In human beings, multiple genes are involved in the inheritance of

• a) Skin colour
• b) Phenylketonuria
• c) Colour blindness
• d) Sickle cell anaemia

Answer: Skin colour

Question: Haemophilic man marries a normal woman. Their offsprings will be

• a) All normal
• b) All girls haemophilic
• c) All boys haemophilic
• d) All haemophilic

Answer: All normal

Question: A marriage between normal visioned man and colour blind woman will produce offspring

• a) Colour blind sons and carrier daughters
• b) 50% colourblind sons and 50% carrier daughters
• c) Colour blind sons and 50% carrier daughters
• d) Normal males and carrier daughters

Answer: Colour blind sons and carrier daughters

Question: In hybridization, Tt × tt gives rise to the progeny in the ratio

• a) 1 : 1
• b) 1 : 2
• c) 1 : 2 : 1
• d) 2 : 1

Answer: 1 : 1

Question: According to Mendelism, which character shows dominance

• a) Green pod colour
• b) Green colour in seed coat
• c) Terminal position of flower
• d) Wrinkled seeds

Answer: Green pod colour

Question: Due to the cross between TTRr × ttrr the resultant progenies show what percent of tall, red flowered plants?

• a) 50%
• b) 75%
• c) 25%
• d) 100%

Answer: 50%

Question: In Drosophila, the XXY condition leads to femaleness whereas in human beings the same condition leads to Klienfelter’s syndrome in male. It proves

• a) In human beings, Y chromosome is active in sex determination
• b) Y chromosome is active in sex determination in both human beings and Drosophila
• c) In Drosophila, Y chromosome decides femaleness
• d) Y chromosome of man has genes for syndrome

Answer:  In human beings, Y chromosome is active in sex determination

Question: Independent assortment of genes does not take place when

• a) Genes are linked and located on same chromosome
• b) Genes are located on homologous chromosomes
• c) Genes are located on non-homogenous chromosomes
• d) All of these

Answer: Genes are linked and located on same chromosome

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

• a) Absence of starch branching enzyme
• b) Invertase
• c) Amylase
• d) Diastase

Answer: Absence of starch branching enzyme

Question: Ratio of complementary genes is

• a) 9 : 7
• b) 9 : 3 : 3 : 4
• c) 12 : 3 : 1
• d) 9 : 3 : 4

Answer: 9 : 7

Question: When both parental alleles are expressed together, it is called

• a) Co-dominance
• b) Dominance
• c) Incomplete dominance
• d) Pseudodominance

Answer: Co-dominance

Question: A and B genes are linked. What shall be genotype of progeny in a cross between AB/ab and ab/ab?

• a) AaBb and aabb
• b) AAbb and aabb
• c) AABB and aabb
• d) aaBB × Aabb

Answer: AaBb and aabb

Question: Probability of four sons to a couple is

• a) 1/16
• b) 1/32
• c) 1/8
• d) 1/4

Answer: 1/16

Question: If recombination frequency between AB genes is 20% and BC gene is 40% and interference is 30% in thecase of double cross over then what will be coincidance  under this condition?

• a) 0.7
• b) 5.6
• c) 8
• d) 2.4

Answer: 0.7

Question: Male XX and female XY sometime occur due to

• a) Transfer of segments in X and Y chromosome
• b) Hormonal imbalance
• c) Deletion
• d) Aneuploidy

Answer: Transfer of segments in X and Y chromosome

Question: Number of Barr body in XXXX female is

• a) 3
• b) 4
• c) 2
• d) 1

Answer: 3

Question: Extranuclear inheritance occurs in

• a) Killer Paramecium
• b) Killer Amoeba
• c) Euglena
• d) Hydra

Answer: Killer Paramecium

Question: Which of the following is correct match?

• a) Down’s syndrome - 21^st chromosome
• b) Haemophilia – Y-chromosome
• c) Sickle cell anaemia – X-chromosome
• d) Parkinson’s disease – X & Y chromosome

Answer: Down’s syndrome - 21^st chromosome

Question: How many genome types are present in a typical green plants cell?

• a) Two
• b) Three
• c) More than ten
• d) More than five

Answer: Two

Question: Which of the following is an example of sex linked disease?

• a) Colour blindness
• b) Syphilis
• c) Gonorrhoea
• d) AIDS

Answer: Colour blindness

Question: Which of the following is an example of pleiotropy?

• a) Sickle cell anaemia
• b) Colour blindness
• c) Thalassemia
• d) Haemophilia

Answer: Sickle cell anaemia

Question: A gene is said to be dominant if

• a) It expresses its effect both in homozygous and heterozygous condition
• b) It expresses its effect only in heterozygous condition
• c) It expresses its effect only in homozygous state
• d) It never expresses it’s effect in any condition

Answer: It expresses its effect both in homozygous and heterozygous condition

Question: On selfing a plant of F₁-generation with genotype ‘’AABbCC’’, the genotypic ratio in F₂ -generation will be

• a) 1 : 2 : 1
• b) 9 : 3 : 3 : 1
• c) 1 : 1
• d) 27 : 9 : 9 : 9 : 3 : 3 : 3 : 1

Answer:  1 : 2 : 1

Question: A diseased mans marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is

• a) Sex linked dominant
• b) Sex linked recessive
• c) Sex limited character
• d) Sex limited character

Answer: Sex linked dominant

Question: A diseased mans marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is

• a) Sex linked dominant
• b) Sex linked recessive
• c) Sex limited character
• d) Autosomal dominant

Answer: Sex linked dominant

Question: Down’s syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring is produced by an affected mother and a normal father?

• a) 50%
• b) 25%
• c) 75%
• d) 100%

Answer: 50%

Question: Which one of the following discoveries resulted in a Nobel Prize?

• a) X-rays induce sex-linked recessive lethal mutations
• b) Recombination of linked genes
• c) Cytoplasmic inheritance
• d) Genetic engineering

Answer: X-rays induce sex-linked recessive lethal mutations

Question: Two crosses between the same pair of genotypes or phenotypes in which the sources of the gametes are reversed in one cross, is known as

• a) Reciprocal cross
• b) Test cross
• c) Dihybrid cross
• d) Reverse cross

Answer: Reciprocal cross

Question: The genes controlling the seven pea characters studied by Mendel are now known to be located on how many different chromosomes?

• a) Four
• b) Five
• c) Six
• d) Seven

Answer: Four

Question: Which one of the following traits of garden pea studied by Mendel was a recessive feature ?

• a) Green seed colour
• b) Green pod colour
• c) Round seed shape
• d) Axial flower position

Answer: Green seed colour

Question: Moustaches, beard and horseness in voice in human males are examples of

• a) Sex limited traits
• b) Sex determining traits
• c) Sex-linked traits
• d) Sex differentiating traits

Answer:  Sex limited traits

Question: In Drosophila, the sex is determined by

• a) The ratio of number of X chromosomes to the sets of autosomes
• b) X and Y chromosomes
• c) The ratio of X-chromosomes to the pairs of autosomes
• d) Whether the egg is fertilized or develops parthenogenetically

Answer:  The ratio of number of X chromosomes to the sets of autosomes

Question:  One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of F₂ progenies that mutation is found in

• a) None of the progenies
• b) Fifty percent of the progenies
• c) One-third of the progenies
• d) All the progenies

Answer: None of the progenies

Question: Lack of independent assortment of two genes A and B in fruit fly Drosophila is due to

• a) Linkage
• b) Crossing over
• c) Recombination
• d) Repulsion

Answer: Linkage

Question: What kind of evidence suggested that man is more closely related with chimpanzee than with other hominoid apes?

• a) Evidence from DNA extracted from sex chromosomes, autosomes
• b) Evidence from fossil remains, and the fossil mitochondrial DNA alone
• c) Comparison of chromosomes morphology only
• d) Evidence from DNA from sex chromosomes only

Answer: Evidence from DNA extracted from sex chromosomes, autosomes

Question: The recessive genes located on X-chromosome of humans are always

• a) Expressed in males
• b) Lethal
• c) Sub-lethal
• d) Expressed in females

Answer: Expressed in males

Question: A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic geneh. What proportion of his sperms will be abh?

• a) 1/8
• b) 1/32
• c) 1/16
• d) 1/4

Answer: 1/8

Question: A self-fertilizing trihybrid plant forms

• a) 8 different gametes and 64 different zygotes
• b) 8 different gametes and 16 different zygotes
• c) 4 different gametes and 16 different zygotes
• d) 8 different gametes and 32 different zygotes

Answer: 8 different gametes and 64 different zygotes

Question: There are three genes a, b, c. Percentage of crossing over between a and b is 20%, b and c is 28% and a and c is 8%. What is the sequence of genes on chromosome?

• a) b, a, c
• b) a, b, c
• c) a, c, b
• d) None of these

Answer:  b, a, c

Question:   The linkage map of X-chromosome of fruit fly has 66 units, with yellow body gene (y) at one end and bobbed hair (b) gene at the other end. The recombination frequency between these two genes (y and b) should be

• a)

  

• b)

  

• c) 100%
• d) 66%

Answer: 

Question:  In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plantwith RRTt genotype is crossed with a plant that is rrtt

• a) 50% will be tall with red fruit
• b) 50% will be tall with red fruit
• c) 25% will be tall with red fruit
• d) 75% will be tall with red fruit

Answer: 50% will be tall with red fruit

Question: A normal woman, whose father was colour blind is married to a normal man. The sons would be

• a) 50% colour blind
• b) All normal
• c) All colour blind
• d) 75% colour blind

Answer: 50% colour blind

Question: De Vries gave his mutation theory on organic evolution while working on

• a) Oenothera lamarckiana
• b) Pisum sativum
• c) Drosophila melanogaster
• d) Althea rosea

Answer:  Oenothera lamarckiana

Question: Triticale, the first man-made cereal crop, has been obtained by crossing wheat with

• a) Rye
• b) Barley
• c) Pearl millet
• d) Sugarcane

Answer: Rye

Question: Normally DNA molecule has A-T, G-C pairing. However, these bases can exist in alternative valency status owing to rearrangements called

• a) Tautomerisational mutation
• b) Point mutation
• c) Frame-shift mutation
• d) Analog substitution

Answer: Tautomerisational mutation

Question: The most striking example of point mutation is found in a disease called

• a) Sickle cell anaemia
• b) Edward syndrome
• c) Night blindness
• d) Down’s syndrome

Answer: Sickle cell anaemia

Question: Identify the one, which causes gene mutation

• a) X-rays
• b) Crossing over
• c) Colchicine
• d) Granoson

Answer: X-rays

Question: The mutations are mainly responsible for

• a) Variation in organisms
• b) Increasing the population rate
• c) Maintaining genetic continuity
• d) Constancy in organisms

Answer: Variation in organisms

Question: Which of the following is the main category of mutation?

• a) Genetic mutation
• b) Heterosis
• c) None of these
• d) Somatic mutation

Answer: Genetic mutation

Question: Change in sequence of nucleotide in DNA is called

• a) Mutation
• b) Recombination
• c) Translation
• d) Mutagen

Answer: Mutation

Question: When a cluster of genes show linkage behaviour they

• a) Do not show independent assortment
• b) Do not show a chromosome map
• c) Show recombination during meiosis
• d) Induce cell division

Answer: Do not show independent assortment

Question: Genetic map is one that

• a) Establishes sites of the genes on a chromosome
• b) Establishes the various stages in gene evolution
• c) Shows the stages during the cell division
• d) Shows the distribution of various species in a region

Answer: Establishes sites of the genes on a chromosome

Question: In mutational event, when adenine is replaced by guanine, it is a case of

• a) Transition
• b) Transversion
• c) Transcription
• d) Frame shift mutation

Answer: Transition

Question: The most likely reason for the development of resistance against pesticides in insects damaging a crop is

• a) Random mutations
• b) Directed mutations
• c) Genetic recombination
• d) Acquired heritable changes

Answer: Random mutations

Question: When two genetic loci produce identical phenotypes in cis and trans position, they are considered to be

• a) Pseudoalleles
• b) Multiple alleles
• c) The parts of same gene
• d) Different genes

Answer: Pseudoalleles

Question: What base is responsible for hot spots for spontaneous point mutations?

• a) 5-methylcytosine
• b) Guanine
• c) Adenine
• d) 5-bromouracil

Answer: 5-methylcytosine

Question: Nucleus of a donor embryonal cell/somatic cell is transferred to an enucleated egg cell. Then after the formation of organism, what shall be true?

• a) Organism will have extranuclear genes of recipient cell
• b) Organism will have extranuclear genes of the donor cell
• c) Organism will have extranuclear genes of both donor and recipient cell
• d) Organism will have nuclear genes of recipient cell

Answer: Organism will have extranuclear genes of recipient cell