CBSE Class 10 Science Heredity and Evolution MCQs Set 03

Question. Allele that cannot express itself in presence of another is 
(a) codominant
(b) dominant
(c) recessive
(d) complementary.
Answer : C

Question. In Drosophila, red eye character is dominant over white eye character. When a homozygous red-eyed individual is crossed with a homozygous white-eyed individual, and individuals of F₁ generation are intercrossed, 12 individuals are produced. White-eyed individuals of these will be 
(a) three
(b) six
(c) nine
(d) twelve.
Answer : A

Question. Identify P, Q, R and S in the case of normal human from given flow chart and select the correct option. 
 
      P   Q   R   S
(a) XX XY XY XX
(b) XY XX XX XY
(c) XXX XY XYY XXX
(d) XO XX XX XO
Answer : B

Question. Segregation of alleles takes place during 
(a) meiosis
(b) cleavage
(c) fertilisation
(d) crossing over.
Answer : A

Question. The information source for making proteins in the cell is the 
(a) chromosome
(b) DNA
(c) enzyme
(d) nucleus.
Answer : B

Question. A true breeding tall and smooth-seeded pea plant was crossed with a true breeding dwarf and wrinkled-seeded plant. All the F1 plants were tall and demonstrate 
(a) principle of assortment of characters
(b) that recombination of characters appears in F₂ generation
(c) that P tall plants were heterozygous
(d) that tallness was dominant over dwarfness.
Answer : D

Question. The percentage of yr gamete produced by YyRr parent will be 
(a) 25%
(b) 50%
(c) 75%
(d) 12.5%.
Answer : A

Question. Two variants found in human population are shown in the given figure. Identify them and select the correct option. 
(i) This is an inherited character.
(ii) This is acquired during lifetime.
(iii) This is a non-genetic trait.
(a) (ii) and (iii)
(b) Only (i)
(c) (i) and (iii)
(d) Only (ii)
Answer : B

Question. The reason why some mutations, which are harmful, do not get eliminated from gene pool is that 
(a) they are recessive and carried by heterozygous individuals
(b) they are dominant and show up more frequently
(c) genetic drift occur because of a small population
(d) they have future survival value.
Answer : A

Question. Mutation is a 
(a) change that causes evolution when inherited
(b) change which affects the parents only but never inherited
(c) change which affects the offspring of F₂ generation only
(d) factor responsible for plant growth.
Answer : A

Question. Refer to the given figure and select the correct statement(s) regarding it. 

(i) It is a monohybrid cross.
(ii) Red flower colour trait is dominant over white flower colour trait.
(iii) Both the traits red flower colour and white flower colour were inherited in F₁ plants, but only red flower trait was expressed.
(a) (ii) and (iii)
(b) Only (i)
(c) Only (ii)
(d) (i), (ii) and (iii)
Answer : D

Question. In plant, tall phenotype is dominant over dwarf phenotype, and the alleles are designated as T and t, respectively. Upon crossing one tall and one dwarf plant, total 250 plants were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parent plants were 
(a) TT × TT
(b) TT × tt
(c) Tt × Tt
(d) Tt × tt.
Answer : D

Question. Mendel performed a cross between two garden pea plants; one with round and green seed and the other with yellow and wrinkled seed as shown below. 


(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) and (iii)
(d) (i) and (iv)
Answer : A

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

Question. An allele is said to be dominant if 
(a) it is expressed in both homozygous and heterozygous conditions
(b) it is expressed only in second generation
(c) it is expressed only in heterozygous condition
(d) it is expressed only in homozygous condition.
Answer : A

Question. What will be the percentage of purple stemmed plants in the F2 generation, when the F1 generation resulted due to cross breeding of green stemmed (GG) tomato plants with purple stemmed (gg) tomato plants, are self pollinated? 
(a) 10%
(b) 25%
(c) 75%
(d) 50%
Answer : B

Question. If a genotype consists of different types of alleles, it is called 
(a) homozygous
(b) heterozygous
(c) monoallelic
(d) uniallelic.
Answer : B

Question. Which of the following represents the characteristic of a pleiotropic gene? 
(a) Controls sexual characters.
(b) Present only in prokaryotes.
(c) Controls one character in association with the other.
(d) Control more than one character.
Answer : D

Question. In human beings, the statistical probability of having a male child is 
(a) 25%
(b) 50%
(c) 75%
(d) 60%.
Answer : B

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 F1 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) F1 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 F2 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 F2 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 F1 produced is self pollinated to produce F2 ratio of true breeding tall and true breeding short plant in F2 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

Question. Which of the following is a totally impossible outcome of Mendel’s Experiment (cross breeding pure bred tall and short pea plants)
(a) 3 tall 1 short plant
(b) 24 tall and 8 short plants
(c) 8 tall and 0 short plants
(d) 4 tall plants and 1 medium-height plant.
Answer : D

Question. Which one is a possible progeny in F₂ generation of pure bred tall plant with round seed and short plant with wrinkled seeds?
(a) Tall plant with round seeds
(b) Tall plant with wrinkled seeds
(c) Short plant with round seed
(d) All of the above
Answer : D