MCQ Questions for Class 12 Biology: Ch 5 Principles of Inheritance and Evolution
1. 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
► (c) aabb
2. Turner syndrome is
(a) XYY
(b) XO
(c) XXX
(d) XXY
► (b) XO
3. Haemophilia is due to
(a) Factor-VIII
(b) Factor-VII
(c) Factor-IX
(d) Factor-VI
► (a) Factor-VIII
4. In the hexaploid wheat, the haploid (n) and basic (X) numbers of chromosomes are _____.
(a) n = 7 and X = 21
(b) n = 21 and X = 21
(c) n = 21 and X = 7
(d) n = 21 and X = 14
► (c) n = 21 and X = 7
5. In sickle-cell anaemia glutamic acid is replaced by valine. Which one of the following triplet codes for valine?
(a) G G G
(b) A A G
(c) G A A
(d) G U G
► (d) G U G
6. Sickle-cell anaemia is
(a) X-linked recessive inheritance
(b) Autosomal dominant inheritance
(c) Autosomal recessive inheritance
(d) X-linked dominant inheritance
► (c) Autosomal recessive inheritance
7. Which of the following terms represent a pair of contrasting characters?
(a) Homozygous
(b) Co-dominant genes
(c) Heterozygous
(d) Allelomorphs
► (d) Allelomorphs
8.Which one of the following conditions in humans. is correctly matched with its chromosomal abnormality/linkage?
(a) Klinefelters syndrome-44 autosomes + XXY
(b) Colour blindness - Y-linked
(c) Erythroblastosis foetalis - X-linked
(d) Downs syndrome - 44 autosomes + XO
► (a) Klinefelters syndrome-44 autosomes + XXY
9. Point mutation involves
(a) Change in single base pair
(b) Deletion
(c) Insertion
(d) Duplication
► (a) Change in single base pair
10. Which one of the following conditions correctly describes the manner of determining the sex in the given example?
(a) Homozygous sex chromosomes (ZZ) determine female sex in birds.
(b) XO type of sex chromosomes determine male sex in grasshopper
(c) XO condition in human as found in Turner syndrome, determines female sex.
(d) Homozygous sex chromosomes (XX) produce male in Drosophila.
► (b) XO type of sex chromosomes determine male sex in grasshopper
11. A human male produces sperms with the 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
► (d) AaBb
12. When two unrelated individuals or lines are crossed, the performance of F1 hybrid is often superior to both parents. This phenomenon is called:
(a) Heterosis
(b) Transformation
(c) Splicing
(d) Metamorphosis
► (a) Heterosis
13. When alleles of two contrasting characters are present together, one of the character express and the other remains hidden. This is the________.
(a) Law of segregation
(b) Law of independent assortment
(c) Law of dominance
(d) Law of purity of gametes
► (c) Law of dominance
14. F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1. It represents in case of
(a) Monohybrid cross with complete dominance
(b) Monohybrid cross with incomplete dominance
(c) Dihybrid Cross
(d) Co – Dominance
► (b) Monohybrid cross with incomplete dominance
15. In Mendel’s experiment 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 × rryy?
(a) only wrinkled seeds with yellow cotyledons
(b) only wrinkled seeds with green cotyledons
(c) Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
(d) only round seeds with green cotyledons
► (c) Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
16. Mutations which arise suddenly in nature are called
(a) Spontaneous mutations
(b) Gene mutations
(c) Induced mutations
(d) Chromosomal mutations
► (a) Spontaneous mutations
17. A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. His son also marries a woman whose family has no history of color blindness. What is the probability of their grandson through the Son being colour blind?
(a) 1
(b) 0.5
(c) 0.25
(d) Nil
► (c) 0.25
18. If a colour blind woman marries a normal visioned man, their sons will be
(a) one - half colour blind and one - half normal
(b) three-fourths colour blind and one-fourth normal
(c) all colour blind
(d) all normal visioned
► (c) all colour blind
19. 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) 0.4
(b) 0.5
(c) 0.6
(d) 0.7
► (c) 0.6
20. Both sickle cell anemia and Huntington's chorea are
(a) congenital disorders
(b) pollutant-induced disorders
(c) virus-related diseases
(d) bacteria - related diseases
► (a) congenital disorders
21. A certain road accident patient with unknown blood group needs immediate blood transfusion. His one doctor friend at once offers his blood. What was the blood group of the donor?
(a) Blood group B
(b) Blood group AB
(c) Blood group O
(d) Blood group A
► (c) Blood group O
22. Alleles are:
(a) true breeding homozygotes
(b) different molecular forms of a gene
(c) heterozygotes
(d) different phenotype
► (b) different molecular forms of a gene
24. Mutations can be induced with :
(a) infra red radiations
(b) I AA
(c) ethylene
(d) gamma radiations
► (d) gamma radiations
25. Which of the following statements is true regarding the “law of independent assortment”?
(a) Independent assortment leads to variation.
(b) Independent assortment leads to formation of new combinations of characters.
(c) Factors assort independent of each other when more than one pair of characters are present together.
(d) All of the above
► (d) All of the above
26. Fruit colour in squash in an example of:
(a) Recessive epistasis
(b) Dominant epistasis
(c) Complementary genes
(d) Inhibitory genes
► (b) Dominant epistasis
27. Crossing over occurs at:
(a) Single-strand stage of chromosome during prophase
(b) Four strand stage of panchytene
(c) Metaphase-II of meiosis
(d) Two-strand stage during zygotne
► (b) Four strand stage of panchytene
28. Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child ?
(a) Two X chromosomes
(b) Only one Y chromosome
(c) Only one X chromosome
(d) One X and one Y chromosome
► (a) Two X chromosomes
29. A self-fertilizing trihybrid plant forms:
(a) 8 different gametes and 16 different zygotes
(b) 8 different gametes and 32 different zygotes
(c) 4 different gametes and 16 different zygotes
(d) 8 different gametes and 64 different zygotes
► (d) 8 different gametes and 64 different zygotes
30. Sickle cell anaemia has not been eliminated from the African population because
(a) it is not a fatal disease
(b) it provides immunity against malaria
(c) it is controlled by dominant genes
(d) it is controlled by recessive genes
► (b) it provides immunity against malaria
31. Linkage is the_________.
(a) Physical association of two genes present on same chromosome
(b) Physical association of two genes present on different chromosome
(c) Generation of non-parental gene combination
(d) Generation of parental gene combination
► (a) Physical association of two genes present on same chromosome
32. The genetic defect - Adenosine deaminase (ADA) deficiency may be cured permanently by:
(a) administering adenosine deaminase activators.
(b) introducing bone marrow cells producing ADA into cells at early embryonic stages.
(c) enzyme replacement therapy.
(d) periodic infusion of genetically engineered lymphocytes having functional ADA cDNA.
► (b) introducing bone marrow cells producing ADA into cells at early embryonic stages.