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: 0.5

Question: The term "Linkage" was coined by

• a) T.H. Morgan
• b) T. Boveri
• c) G. Mendel
• d) W. Sutton

Answer: T.H. Morgan

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: Controls multiple traits in an individual

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: Pod length

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: Both alleles independently expressed in the heterozygote

Question:

• a) Autosomal recessive
• b) X-linked recessive
• c) Autosomal dominant
• d) X-linked dominant

Answer: Autosomal recessive

Question: Alleles are

• a) Different molecular forms of a gene
• b) Different phenotype
• c) Heterozygotes
• d) True breeding homozygotes

Answer: Different molecular forms of a gene

Question: The movement of a gene from one linkage group to another is called

• a) Translocation
• b) Duplication
• c) Inversion
• d) Crossing over

Answer: Translocation

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: At the same locus of the chromosome

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: Formation of abnormal ova in the mother

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: Seven

Question: Fruit colour in squash is an example of

• a) Dominant epistasis
• b) Inhibitory genes
• c) Recessive epistasis
• d) Complementary genes

Answer: Dominant epistasis

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: 50%

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: Has 45 chromosomes with XO

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: 0.6

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: 25%

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: Codominance

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: Co-dominance

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: The genes are tightly linked

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

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: Monohybrid cross with incomplete dominance

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: Zero percent

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: Determine the genotype of a plant at F₂

Question: Represented below is the inheritance pattern of a certain type of traits in humans. Which one of the following conditions could be an example of this pattern?

• a) Haemophilia
• b) Thalassemia
• c) Sickle cell anaemia
• d) Phenylketonuria

Answer: Haemophilia

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: Change in a single base pair of DNA does not cause mutation

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: XO type of sex chromosomes determine male sex in grasshopper

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: Heterosis

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: The F₁ hybrid with a double recessive genotype

Question:

• a) Four
• b) Two
• c) One
• d) Three

Answer: Four

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: Alleles do not show any blending and both the characters recover as such in F₂ generation

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: Test cross

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: Tightly linked genes on the same chromosome show very few recombinations

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: Test cross

Question:

• a) The female parent is heterozygous
• b) The parents could not have had a normal daughter for this character
• c) The trait under study could not be colourblindness
• d) The male parent is homozygous dominant

Answer: The female parent is heterozygous

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: Four

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: It completes life cycle in about two weeks

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: Rr

Question:  Which one of the following symbols and its representation, used in human pedigree analysis is correct?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Point mutation involves

• a) Change in single base pair
• b) Deletion
• c) Insertion
• d) Duplication

Answer: Change in single base pair

Question:

• a) Inheritance of a condition like phenylketonuria as an autosomal recessive trait
• b) The pedigree chart is wrong as this is not possible
• c) Inheritance of a recessive sex-linked disease like haemophilia
• d) Inheritance of a sex-linked inborn error of metabolism like phenylketonuria

Answer:  Inheritance of a condition like phenylketonuria as an autosomal recessive trait

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: Baldness is a sex-limited trait

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: 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 syndrome - 44 autosomes + XXY
• b) Erythroblastosis foetalis - X-linked
• c) Down syndrome - 44 autosomes + XO
• d) Colour blindness - Y-linked

Answer: Klinefelter syndrome - 44 autosomes + XXY

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: n = 21 and x = 7

Question: Inheritance of skin colour in humans is an example of

• a) Polygenic inheritance
• b) Chromosomal aberration
• c) Codominance
• d) Point mutation

Answer: Polygenic inheritance

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: Crossing of one F₁ progeny with male parent

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: Higher number of the parental types

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: 50 : 50

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: AaBb

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: Ripe banana

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: Genotype and environment interactions

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: Cytoplasmic

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: Two

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: Skin colour in humans

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:  Round seeds with yellow cotyledons and wrinkled seeds with yellow cotyledons

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: Crossing the F₁ hybrid with a double recessive genotype

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: All colourblind

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: Loss of half of the long arm of chromosome 5

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: Sex-linked recessive

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:  0.48

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: May be colourblind or may be of normal vision

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: This disease is due to an X-linked recessive mutation

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: Down syndrome

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: aabb

Question: Which of the following is not a hereditary disease?

• a) Cretinism
• b) Cystic fibrosis
• c) Thalassaemia
• d) Haemophilia

Answer: Cretinism

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: They have endoreduplicated chromosomes

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: Mutations as well as recombination

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: It confirms that DNA is the carrier of genetic information

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: Due to the genetic make up of the particular sperm which fertilizes the egg

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: Three copies of chromosome 21