CBSE Class 10 Science Heredity and Evolution MCQs Set H

Question. Which of the following statement is incorrect?
(a) For every hormone there is a gene.
(b) For every protein there is a gene.
(c) For production of every enzyme there is a gene.
(d) For every molecule of fat there is a gene.
Answer: d

Question. A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
(a) Tallness is the dominant trait.
(b) Shortness is the dominant trait.
(c) Tallness is the recessive trait.
(d) Height of pea plant is not governed by gene ‘T’ or ‘t’.
Answer: a

Question. A zygote which has an X-chromosome inherited from the father will develop into a
(a) Boy.
(b) Girl.
(c) X- chromosome does not determine the sex of a child.
(d) Either boy or girl.
Answer: b

Question. If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant, (rrYY) the seeds produced in F1 generation are :
(a) Round and yellow.
(b) Round and green.
(c) Wrinkled and green.
(d) Wrinkled and yellow.
Answer: a

Question. Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be
(a) Double fertilization.
(b) Self-pollination.
(c) Cross fertilization.
(d) No fertilization.
Answer: c

Question. The maleness of a child is determined by
(a) The X chromosome in the zygote.
(b) The Y chromosome in zygote.
(c) The cytoplasm of germ cell which determines the sex.
(d) Sex is determined by chance.
Answer: b

Question. The number of pair (s) of sex chromosomes in the zygote of humans is:
(a) One.
(b) Two.
(c) Three.
(d) Four.
Answer: a

Assertion and Reason Based MCQs :

Directions : In the following questions, A statement of Assertion (a) is followed by a statement of Reason (R). Mark the correct choice as.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is NOT the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is true.

Question. Assertion (a): In humans, males play an important role in determining the sex of the child.
Reason (R): Males have two X chromosomes.
Answer: c

Question. Assertion (a): Mendel choose a number of varieties of garden pea as plant material for his experiments.
Reason (R): Garden pea has well defined characters and is bisexual.
Answer: a

Question. Assertion (a): Mendel in his experiment selected only two characters of seed.
Reason (R): He studied single character at one time.
Answer: d

Question. Assertion: A zygote with two X chromosomes develops into a boy.
Reason: If the egg cell carrying an X chromosome fuses with the sperm carrying a Y chromosome, the resulting child would be a boy.
Answer: d

Question. Assertion (a): Mendel proposed the law of inheritance of traits from the first generation to the next generation.
Reason (R): Mendel’s Law of segregation is also known as “Law of purity of gametes.
Answer: b

Question. Assertion: A geneticist crossed a pea plant having violet flowers with a pea plant having white flowers, he got all violet flowers in first generation.
Reason: White colour gene is not passed on to next generation.
Answer: c

Case Based Questions:

I. Read the passage and answer the following questions.
In a cross between plants with purple flowers and plants with white flowers, the offspring of F1 generation all had white flowers. When the F1 generation was self-crossed, it was observed in the F2 generation that out of 100, 75 flowers were white. Make a cross and answer the following questions:

Question. Which of these is not the genotype of F2 progeny?
(a) WW
(b) Ww
(c) ww
(d) Wp

Answer: d

Question. The ratio of ‘White: Purple’ flowers in the F2 generation is:
(a) 3 : 1
(b) 1 : 2
(c) 1 : 3
(d) 2 : 1

Answer: a

Question. The above cross is known as:
(a) Monohybrid cross
(b) Dihybrid cross
(c) Test cross
(d) Back cross

Answer: a

Question. In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F1 generation is:
(a) 25%
(b) 50%
(c) 75%
(d) 100%

Answer: b

III. Read the given passage and answer the following questions.
Seema crossed pure breed pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were cross-breed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Question. A-D are __________ and C-B are _______ type of seeds.
(a) Round green and wrinkled yellow respectively
(b) Round yellow and wrinkled green respectively
(c) Wrinkled green and round green respectively
(c) Wrinkled green and round yellow respectively

Answer: a

Question. Which one of these will be produced in maximum number in the F2 generation?
(a) A-B
(b) A-D
(c) Both (a) and (b)
(d) None of these

Answer: a

Question. What are A-B type of seeds?
(a) Round -yellow
(b) Round- green
(c) Wrinkled- yellow
(d) Wrinkled- green

Answer: a

Question. A and B are _____________ traits.
(a) dominant
(b) recessive
(c) Both (a) and (b)
(d) None of these

Answer: a

II. Study the given cross showing self pollination in F1 and answer the following questions from 
RRYY × rryy Parents
(Round Yellow) (Wrinkled Green)
RrYy × ________ F1 generation
(Round Yellow)

Question. The ratio of the combination of characters in the F2 progeny is:
(a) 3 : 1
(b) 1 : 2 : 1
(c) 1 : 1 : 1
(d) 9 : 3 : 3 : 1

Answer: d

Question. A Mendelian experiment consists of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short.
This suggests that the genetic make-up of the tall parent cod depicted as
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw

Answer: c

Question. The missing blank in the above cross is:
(a) RrYy
(b) RRYY
(c) RryY
(d) rryy

Answer: a

Question. The combination of characters in the F2 progeny are:
(a) Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green
(b) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green
(c) Round Yellow : Round Green : Wrinkled Green: Wrinkled yellow
(d) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green

Answer: a

HEREDITY AND EVOLUTION:

Question. Mendel conducted his hybridisation experiment with :-
(a) Chick pea
(b) Pigeon pea
(c) Garden pea
(d) Wild pea
Answer: C

Question. Mendel studied seven contrasting characters for his breeding experiment with Pisum sativum, which of the following character did he not use :-
(a) Pod colour
(b) Pod shape
(c) Leaf shape
(d) Plant height
Answer: C

Question. The main reason of Mendel's successs in discovering the principles of inheritance was :-
(a) He considered each character separately
(b) He was lucky not to encounter linkage problem
(c) The plant was pure breeding
(d) All the above
Answer: D

Question. Mendel was lucky in the choice of the material of his experiments, among the following, which contributed, to his success ?
(a) He observed distinct inherited traits
(b) He qualitatively analysed his data
(c) He liked pea plants
(d) He considered only one character at one time
Answer: D

Question. The year 1990 AD is highly significant for genetics due to :-
(a) Principle of linkage
(b) Chromosome theory of heredity
(c) Rediscovery of Mendelism
(d) Discovery of genes
Answer: C

Question. Genotype means :-
(a) Genetic composition of the individual
(b) Genetic composition of the germ cell
(c) Genetic composition of plastids
(d) Genetic compositon of an organ
Answer: A

Question. The physical manifestation of an organism's genes is its :-
(a) Environment
(b) Phenotype
(c) Genetic code
(d) Genotype
Answer: B

Question. An organism with two identical alleles of a gene in a cell is called :-
(a) Homozygous
(b) Domainant
(c) Heterozygous
(d) Hybrid
Answer: A

Question. When an individual is having both the alleles of contrasting characters it is said to be :-
(a) Heterozygous
(b) Dioecious
(c) Monoecious
(d) Linked genes
Answer: A

Question. When an allele fails to express itself in \( F_1 \) generation in the presence of other allele, the former is said to be :-
(a) Recessive
(b) Codominant
(c) Complementary
(d) Epistatic
Answer: A

Question. Alleles are :-
(a) Homologous chromosome
(b) Chromosome that have crossed over
(c) Alternate forms of gene
(d) Linked genes
Answer: C

Question. Mendel's laws apply only when :-
(a) \( F_1 \) in monohybrid cross shows two types of individuals
(b) The character are linked
(c) Parents are pure breeding
(d) First pair of contrasting character is dependent upon other pairs
Answer: C

Question. Which of Mendel's procedures differed from those of his predecessor and contributed most of his success ?
(a) He observed many characteristics of each trait
(b) He observed distinct inherited traits
(c) He quantitatively analysed his data
(d) He kept breeding records
Answer: C

Question. If a plant is heterozygous for tallness, the \( F_2 \) generation has both tall and dwarf plants. This proves the principle of :-
(a) dominance
(b) segregation
(c) independent assortment
(d) incomplete dominance
Answer: B

Question. Mendel crossed a pure white flowered recessive pea plant with a dominant pure red flowered plant. The first generation of hybrids from the cross should show :-
(a) 50% white flowers and 50% red flowers
(b) all red flowered plants
(c) 75% red flowered and 25% red flowered plants
(d) all white flowered plants
Answer: B

Question. If a couple has three daughters, what are the chances that the fourth child will be a son ?
(a) 100%
(b) 75%
(c) 50%
(d) 0%
Answer: C

Question. If a heterozygous tall plant is crossed with a homozygous dwarf plant, the proportion of dwarf progeny will :-
(a) 50%
(b) 75%
(c) 100%
(d) 25%
Answer: A

Question. The crossing of a homozygous tall plant with a dwarf would yield \( F_2 \) plants in the ratio of :-
(a) two tall and two dwarf
(b) one homozygous tall, one homozygous dwarf and two heterozygous tall
(c) all homozygous dwarf
(d) all homozygous tall
Answer: B

Question. When a true breeding tall plant is crossed with a true breeding short plant and the \( F_1 \) produced is self pollinated to produce \( F_2 \) ratio of true breeding tall and true breeding short plant in \( F_2 \) will be :-
(a) 1 : 2
(b) 1 : 1
(c) 2 : 1
(d) 1 : 3
Answer: B

Question. Blue eye colour in human is recessive to brown eye colour. The expected children of a marriage between blue-eyed woman and brown-eyed male who had a blue-eyed mother are likely to be :-
(a) all blue-eyed
(b) three blue-eyed and one brown-eyed
(c) all brown-eyed
(d) one blue-eyed and one brown-eyed
Answer: D

Question. The genotype of a dominant parent is determined by crossing it with the recessive parent. This cross is called :-
(a) back cross
(b) test cross
(c) long cross
(d) out cross
Answer: B

Question. The results of a test cross reveal that all the offspring resemble the parent being tested. This parent must be :-
(a) heterozygous
(b) homozygous
(c) recessive
(d) haploid
Answer: B