Class 12 Biology Chapter 5: Principles of Inheritance and Variation – 100 MCQs with Answers
1. The father of genetics is:
Answer: B) Mendel
2. Mendel’s experiments were carried out on:
Answer: C) Pea plant
3. Study of inheritance is called:
Answer: A) Genetics
4. Law of segregation is also known as:
Answer: A) Law of purity of gametes
5. The phenotypic ratio of dihybrid cross is:
Answer: C) 9:3:3:1
6. Test cross is between:
Answer: B) F1 and recessive parent
7. Who rediscovered Mendel’s work?
Answer: C) Correns, de Vries & Tschermak
8. Chromosome theory of inheritance was proposed by:
Answer: B) Sutton & Boveri
9. Genes are located on:
Answer: B) Chromosomes
10. Alternate forms of a gene are called:
Answer: C) Alleles
11. A cross between tall (TT) and dwarf (tt) pea plants produces:
Answer: B) Only tall
12. The term ‘pure line’ was coined by:
Answer: C) Johannsen
13. In incomplete dominance, F1 phenotype is:
Answer: C) Intermediate
14. The number of chromosomes in human somatic cell:
Answer: B) 46
15. Sickle cell anaemia is due to:
Answer: B) Point mutation
16. Colour blindness is a:
Answer: C) Sex-linked trait
17. ABO blood group is an example of:
Answer: C) Multiple alleles
18. The gene for haemophilia is located on:
Answer: A) X chromosome
19. The trait which always appears in F1 is:
Answer: A) Dominant
20. Linkage was first discovered by:
Answer: B) Morgan
21. The genotype of a male with haemophilia is:
Answer: B) XhY
22. The 9:3:3:1 ratio is possible in a cross involving:
Answer: B) Two pairs of alleles
23. Phenotype means:
Answer: A) Physical appearance
24. Mendel’s factor is now called:
Answer: B) Gene
25. Chromosomal disorder among following:
Answer: C) Down’s syndrome
26. Turner’s syndrome individuals are:
Answer: A) XO
27. In Down’s syndrome, the karyotype shows:
Answer: A) Trisomy 21
28. A man with blood group AB marries a woman with O. Offspring’s groups:
Answer: A) A, B
29. The probability of a boy being colour-blind if his mother is a carrier:
Answer: C) 50%
30. A change in a single nucleotide is a:
Answer: C) Point mutation
31. The 3:1 ratio is possible in:
Answer: A) Monohybrid cross
32. Human sex chromosome pair is:
Answer: B) 23
33. Crossing over occurs during:
Answer: B) Prophase I
34. Blood group O is:
Answer: A) Universal donor
35. Gene for colour blindness is:
Answer: B) Sex-linked
36. Genetic makeup of an organism is:
Answer: B) Genotype
37. Haemophilia is more common in males because:
Answer: A) Gene is on X chromosome
38. The karyotype of person with Down’s syndrome:
Answer: C) 47 chromosomes
39. Genotype of a carrier female for colour blindness:
Answer: B) XcX
40. Mendelian disorder among following:
Answer: A) Haemophilia
41. Number of Barr body in normal female is:
Answer: B) 1
42. A universal recipient has blood group:
Answer: A) AB
43. Which chromosome is not an autosome in human:
Answer: C) X
44. Chromosomes are made up of:
Answer: A) DNA & protein
45. Hemoglobin S is seen in:
Answer: A) Sickle cell anaemia
46. Study of chromosomes is:
Answer: B) Karyotyping
47. Mendelian ratio for incomplete dominance:
Answer: C) 1:2:1
48. Point mutation example is:
Answer: A) Sickle cell anaemia
49. Thalassemia affects:
Answer: A) Globin
50. The chromosomal basis of sex determination was explained by:
Answer: A) Sutton
51. Polygenic inheritance controls:
Answer: D) Both A & C
52. Mutation theory was proposed by:
Answer: B) De Vries
53. In humans, sex-linked genes are mostly found on:
Answer: A) X chromosome
54. Phenotypic ratio in F2 generation of a monohybrid cross is:
Answer: B) 3:1
55. Sex determination in humans depends on:
Answer: A) Father
56. Male with XXY chromosomes is:
Answer: B) Klinefelter’s syndrome
57. Chromosome number in Turner’s syndrome:
Answer: B) 45
58. Autosomal recessive disorder is:
Answer: B) Thalassemia
59. Chromosomal mutation includes:
Answer: D) All
60. Mendel’s third law is:
Answer: C) Law of independent assortment
61. Human egg cell contains:
Answer: A) 23 chromosomes
62. The genetic constitution AA is called:
Answer: A) Homozygous dominant
63. Homologous chromosomes are:
Answer: B) Pair of chromosomes carrying same gene loci
64. Inheritance of height in humans is:
Answer: A) Polygenic
65. A gene present on Y chromosome is:
Answer: A) Holandric
66. Sickle cell disease is not cured because:
Answer: D) Both A & C
67. XXY karyotype results in:
Answer: C) Klinefelter
68. A man with hemophilia marries a normal woman, their sons will be:
Answer: A) All normal
69. The number of pairs of sex chromosomes in humans:
Answer: B) 1
70. Down’s syndrome cause is:
Answer: A) Trisomy 21
71. The number of alleles controlling blood groups in humans:
Answer: C) 3
72. Allosomes are:
Answer: B) Sex chromosomes
73. Phenylketonuria is due to:
Answer: A) Enzyme deficiency
74. Thalassemia is:
Answer: C) Autosomal recessive
75. Mendelian inheritance is shown by:
Answer: D) All
76. Pedigree analysis is useful for:
Answer: D) All
77. Male with X chromosome and no Y:
Answer: B) Turner syndrome
78. Who coined the term genetics?
Answer: A) Bateson
79. Gene for sickle cell is located on chromosome:
Answer: C) 11
80. Number of linkage groups in humans:
Answer: B) 23
81. Inheritance of genes located on mitochondria is:
Answer: B) Maternal
82. Drosophila is ideal for genetics studies because:
Answer: A) Short life cycle
83. Y-linked inheritance is called:
Answer: A) Holandric
84. Crossing over increases:
Answer: B) Variability
85. Sickle cell trait is advantageous against:
Answer: A) Malaria
86. Presence of three X chromosomes is:
Answer: C) Superfemale
87. The number of total chromosomes in Turner syndrome:
Answer: B) 45
88. The allele responsible for sickling is:
Answer: B) HbS
89. Father to son inheritance is seen in:
Answer: B) Y-linked
90. Down’s syndrome can be detected by:
Answer: C) Both
91. Gene is a segment of:
Answer: B) DNA
92. Barr body is found in:
Answer: B) Females
93. The number of Barr bodies in Klinefelter’s syndrome:
Answer: B) 1
94. Genes located on same chromosome are called:
Answer: A) Linked genes
95. ABO group is located on chromosome:
Answer: B) 9
96. Colour blindness is absent in:
Answer: A) Girls
97. Which is not a Mendelian disorder?
Answer: C) Down’s syndrome
98. Genetic disorder with trisomy:
Answer: A) Down’s syndrome
99. Y-linked trait is transmitted from:
Answer: A) Father to son
100. Genotype of normal female:
Answer: B) XX