NEET Biology Principles of Inheritance and Variation MCQs Set B

Question. A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colour blind?
(a) 0.5
(b) 0.25
(c) 1
(d) Nil

Answer: A

Question. The term "Linkage" was coined by
(a) T.H. Morgan
(b) T. Boveri
(c) G. Mendel
(d) W. Sutton

Answer: A

Question. A pleiotropic gene
(a) Controls multiple traits in an individual
(b) Is expressed only in primitive plants
(c) Is gene evolved during Pliocene
(d) Controls a trait only in combination with another gene

Answer: A

Question. In his classic experiments on pea plants, Mendel did not use
(a) Pod length
(b) Seed shape
(c) Seed colour
(d) Flower position

Answer: A

Question. A gene showing codominance has
(a) Both alleles independently expressed in the heterozygote
(b) One allele dominant on the other
(c) Alleles tightly linked on the same chromosome
(d) Alleles that are recessive to each other

Answer: A

Question. Alleles are
(a) Different molecular forms of a gene
(b) Different phenotype
(c) Heterozygotes
(d) True breeding homozygotes

Answer: A

Question. The movement of a gene from one linkage group to another is called
(a) Translocation
(b) Duplication
(c) Inversion
(d) Crossing over

Answer: A

Question. Multiple alleles are present
(a) At the same locus of the chromosome
(b) On different chromosomes
(c) On non-sister chromatids
(d) At different loci on the same chromosome

Answer: A

Question. An abnormal human baby with 'XXX' sex chromosomes was born due to
(a) Formation of abnormal ova in the mother
(b) Fusion of two sperm and one ovum
(c) Both
(d) None of these

Answer: A

Question. How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?
(a) Seven
(b) Five
(c) Six
(d) Eight

Answer: A

Question. Fruit colour in squash is an example of
(a) Dominant epistasis
(b) Inhibitory genes
(c) Recessive epistasis
(d) Complementary genes

Answer: A

Question. A man whose father was colour blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour blind ?
(a) 50%
(b) 75%
(c) 0%
(d) 25%

Answer: A

Question. A human female with Turner's syndrome
(a) Has 45 chromosomes with XO
(b) Exhibits male characters
(c) Has one additional X chromosome
(d) Is able to produce children with normal husband

Answer: A

Question. In a population of 1000 individuals 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is
(a) 0.6
(b) 0.7
(c) 0.5
(d) 0.4

Answer: A

Question. If both parents are carriers for thalessemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?
(a) 25%
(b) 50%
(c) 100%
(d) No chance

Answer: A

Question. If two persons with 'AB' blood group marry and have sufficiently large number of children, these children could be classified as 'A' blood group : 'AB' blood group : 'B' blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of
(a) Codominance
(b) Partial dominance
(c) Incomplete dominance
(d) Complete dominance

Answer: A

Question. Which Mendelian idea is depicted by a cross in which the F₁ generation resembles both the parents?
(a) Co-dominance
(b) Law of dominance
(c) Inheritance of one gene
(d) Incomplete dominance

Answer: A

Question. Which of the following statements is not true of two genes that show 50% recombination fequency ?
(a) The genes are tightly linked
(b) The genes show independent assortment
(c) If the genes are present on the same chromosome, they undergo more than one crossovers in every meiosis
(d) The genes may be on different chromosomes

Answer: A

Question. F₂ generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1. It represents a case of
(a) Monohybrid cross with incomplete dominance
(b) Monohybrid cross with complete dominance
(c) Co-dominance
(d) Dihybrid cross

Answer: A

Question. A normal-visioned man whose father was colour-blind, marries a woman whose father was also colour blind. They have their first child as a daughter. What are the chances that this child would be colour-blind?
(a) Zero percent
(b) 100%
(c) 50%
(d) 25%

Answer: A

Question. A test cross is carried out to
(a) Determine the genotype of a plant at F₂
(b) Predict whether two traits are linked
(c) Asses the number of alleles of a gene
(d) Determine whether two species or varieties will breed successfully

Answer: A

Question. Which one of the following is a wrong statement regarding mutations?
(a) Change in a single base pair of DNA does not cause mutation
(b) UV and Gamma rays are mutagens
(c) Cancer cells commonly show chromosomal aberrations
(d) Deletion and insertion of base pairs cause frame-shift mutations

Answer: A

Question. Which one of the following conditions correctly describes the manner of determining the sex in the given example?
(a) XO type of sex chromosomes determine male sex in grasshopper
(b) Homozygous sex chromosomes (ZZ) determine female sex in Birds.
(c) Homozygous sex chromosomes (XX) produce male in Drosophila
(d) None of these

Answer: A

Question. When two unrelated individuals or lines are crossed, the performance of F₁ hybrid is often superior of both its parents. This phenomenon is called
(a) Heterosis
(b) Transformation
(c) Splicing
(d) Metamorphosis

Answer: A

Question. Test cross in plants or in Drosophila involves crossing
(a) The F₁ hybrid with a double recessive genotype
(b) Between two genotypes with dominant trait
(c) Between two genotypes with recessive trait
(d) Between two F₁ hybrids

Answer: A

Question. Which one of the following cannot be explained on the basis of Mendel’s Law of Dominance?
(a) Alleles do not show any blending and both the characters recover as such in F₂ generation
(b) Out of one pair of factors one is dominant, and the other recessive
(c) The discrete unit controlling a particular character is called a factor
(d) Factors occur in pairs

Answer: A

Question. The genotype of a plant showing the dominant phenotype can be determined by
(a) Test cross
(b) Dihybrid cross
(c) Pedigree analysis
(d) Back cross

Answer: A

Question. Select the correct statement from the ones given below with respect to dihybrid cross
(a) Tightly linked genes on the same chromosome show very few recombinations
(b) Tightly linked genes on the same chromosome show higher recombinations
(c) Genes far apart on the same chromosome show very few recombinations
(d) Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones

Answer: A

Question. A cross in which an organism showing a dominant phenotype is crossed with the recessive parent in order to know its genotype is called
(a) Test cross
(b) Dihybrid cross
(c) Back cross
(d) Monohybrid cross

Answer: A

Question. ABO blood grouping is controlled by gene I which has three alleles and show co-dominance. There are six genotypes. How many phenotypes in all are possible?
(a) Four
(b) Five
(c) Three
(d) Six

Answer: A

Question.  The fruit fly Drosophila melanogaster was found to be very suitable for experimental verification of chromosomal theory of inheritance by Morgan and his colleagues because
(a) It completes life cycle in about two weeks
(b) Smaller female is easily recognisable from larger male
(c) A single mating produces two young flies
(d) It reproduces parthenogenetically

Answer: A

Question. In Antirrhinum two plants with pink flowers were hybridized. The F₁ plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR, and white by rr genes
(a) Rr
(b) rr
(c) RR
(d) rrrr

Answer: A

Question. Point mutation involves
(a) Change in single base pair
(b) Deletion
(c) Insertion
(d) Duplication

Answer: A

Question. Select the incorrect statement from the following
(a) Baldness is a sex-limited trait
(b) Small population size results in random genetic drift in a population
(c) Galactosemia is an inborn error of metabolism
(d) Linkage is an exception to the principle of independent assortment in heredity

Answer: A

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) Haploids are reproductively more stable than diploids
(c) Mutagens penetrate in haploids more effectively than diploids
(d) Haploids are more abundant in nature than diploids

Answer: A

Question. Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/ linkage?
(a) Klinefelter syndrome - 44 autosomes + XXY
(b) Erythroblastosis foetalis - X-linked
(c) Down syndrome - 44 autosomes + XO
(d) Colour blindness - Y-linked

Answer: A

Question. In the hexaploid wheat, the haploid (n) and basic (x) numbers of chromosomes are
(a) n = 21 and x = 7
(b) n = 7 and x = 21
(c) n = 21 and x = 21
(d) n = 21 and x = 14

Answer: A

Question. Inheritance of skin colour in humans is an example of
(a) Polygenic inheritance
(b) Chromosomal aberration
(c) Codominance
(d) Point mutation

Answer: A

Question. A common test to find the genotype of a hybrid is by
(a) Crossing of one F₁ progeny with male parent
(b) Crossing of one F₂ progeny with male parent
(c) Crossing of one F₃ progeny with male parent
(d) Crossing of one F₄ progeny with male parent

Answer: A

Question. Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridized, the F₂ segregation will show
(a) Higher number of the parental types
(b) Segregation in the expected 9: 3: 3: 1 ratio
(c) Higher number of the recombinant types
(d) Segregation in 3:1 ratio

Answer: A

Question.  In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in F₁ generation?
(a) 50 : 50
(b) 9 : 1
(c) 1 : 3
(d) 3 : 1

Answer: A

Question. A human male produces sperms with genotypes AB, Ab, aB and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?
(a) AaBb
(b) AaBB
(c) AABb
(d) AABB

Answer: A

Question. Which one of the following is the most suitable, medium for culture of Drosophila melanogaster ?
(a) Ripe banana
(b) Cow dung
(c) Agar agar
(d) Moist bread

Answer: A

Question. Phenotype of an organism is the result of
(a) Genotype and environment interactions
(b) Cytoplasmic effects and nutrition
(c) Mutations and linkages
(d) Environmental changes and sexual dimorphism

Answer: A

Question. In which mode of inheritance do you expect more maternal influence among the offspring ?
(a) Cytoplasmic
(b) Autosomal
(c) Y-linked
(d) X-linked

Answer: A

Question. How many different kinds of gametes will be produced by a plant having the genotype AABbCC?
(a) Two
(b) Nine
(c) Four
(d) Three

Answer: A

Question. Which one of the following is an example of polygenic inheritance?
(a) Skin colour in humans
(b) Production of male honey bee
(c) Flower colour in Mirabilis jalapa
(d) Pod shape in garden pea

Answer: A

Question. In Mendel’s experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy).What are the expected phenotypes in the F₂ generation of the cross RRYY x rryy?
(a) Round seeds with yellow cotyledons and wrinkled seeds with yellow cotyledons
(b) Only wrinkled seeds with green cotyledons
(c) Only wrinkled seeds with yellow cotyledons
(d) Only round seeds with green cotyledons

Answer: A

Question. Test cross involves 
(a) Crossing the F₁ hybrid with a double recessive genotype
(b) Crossing bet
(c) Crossing between two genotypes with recessive trait
(d) Crossing between two F₁ hybrids

Answer: A

Question. If a colourblind woman marries a normal visioned man, their sons will be
(a) All colourblind
(b) Three-fourths colourblind and one-fourth normal
(c) One-half colourblind and one-half normal
(d) All normal visioned

Answer: A

Question. Cri-du-chat syndrome in humans is caused by the
(a)   Loss of half of the long arm of chromosome 5
(b)   Loss of half of the short arm of chromosome 5
(c) Fertilization of an XX egg by a normal Y-bearing sperm
(d) Trisomy of 21st chromosome

Answer: A

Question. A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?
(a) Sex-linked recessive
(b) Sex-limited recessive
(c) Sex-linked dominant
(d) Autosomal dominant

Answer: A

Question.  At a particular locus, frequency of ‘A’ allele is 0.6 and that of ‘a’ is 0.4. What would be the frequency of heterozygotes in a random mating population at equilibrium?
(a) 0.48
(b) 0.36
(c) 0.24
(d) 0.16

Answer: A

Question. A woman with normal vision, but whose father was colour blind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy
(a) May be colourblind or may be of normal vision
(b)   Must be colourblind
(c) Will be partially colourblind since he is heterozygous for the colourblind mutant allele
(d) Must have normal colour vision

Answer: A

Question. Haemophilia is more commonly seen in human males than in human females because
(a) This disease is due to an X-linked recessive mutation
(b) This disease is due to a Y-linked recessive mutation
(c) A greater proportion of girls die in infancy
(d) This disease is due to an X-linked dominant mutation

Answer: A

Question. A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by
(a) Down syndrome
(b) Triploidy
(c) Turner syndrome
(d) Super femaleness

Answer: A

Question.  In order to find out the different types of gametes produced by a pea plant having the genotype AaBb, it should be crossed to a plant with the genotype
(a) aabb
(b) AABB
(c) AaBb
(d) aaBB

Answer: A

Question. Which of the following is not a hereditary disease?
(a) Cretinism
(b) Cystic fibrosis
(c) Thalassaemia
(d) Haemophilia

Answer: A

Question.  The salivary gland chromosomes in the dipteran larvae, are useful in gene mapping because
(a) They have endoreduplicated chromosomes
(b) These are easy to stain
(c) These are much longer in size
(d) These are fused

Answer: A

Question.  Genetic variation in a population arises due to
(a) Mutations as well as recombination
(b) Mutations only
(c) Recombination only
(d) Reproductive isolation and selection

Answer: A

Question.  Which one is the incorrect statement with regards to the importance of pedigree analysis?
(a) It confirms that DNA is the carrier of genetic information
(b) It helps to trace the inheritance of a specific trait
(c) It helps to understand whether the trait in question is dominant or recessive
(d) It confirms that the trait is linked to one of the autosome

Answer: A

Question. In our society women are blamed for producing female children. Choose the correct answer for the sexdetermination in humans
(a) Due to the genetic make up of the particular sperm which fertilizes the egg
(b) Due to the genetic make up of the egg
(c) Due to some defect like aspermia in man
(d) Due to some defect in the women

Answer: A

Question.  Down’s syndrome in humans is due to
(a) Three copies of chromosome 21
(b) Two ‘Y’ chromosomes
(c) Three ‘X’ chromosomes
(d) Monosomy

Answer: A