12th Class Biology Mcqs with Answers Chapter 22 | 2nd year Biology Mcqs With Answers

written by Assad Javaid | August 10, 2021

Chapter 22

Variation and Genetics

Encircle the most appropriate answer among the following options

1. Mendel’s idea that pairs of characters separate during gamete formation is

called the law of choose which one is correct:

  • Particulate inheritance
  • Dominance
  • Segregation
  • Independent assortment

2. The allele that masks the effects of the other and the masked allele are known

as choose which one is correct:

  • Homozygous, heterozygous
  • Homozygous, recessive
  • Dominant, recessive
  • Dominant, incomplete

3. What is the most common outcome in the F2 generation of a cross between a

tall plant and a dwarf plant?

  • 1 tall  choose which one is correct: 1 dwarf
  • 3 tall  choose which one is correct: 1 dwarf
  • 1 tall  choose which one is correct: 2 medium  choose which one is correct: 1 dwarf
  • All tall

4. Two carriers of albinism have four children. One of their children is albino

and the remaining three are normally pigmented. What is the probability

that their next child will be albino?

  • 0%
  • 25%
  • 75%
  • 100%

5. Kathy’s brother has cystic fibrosis. Her husband has no family history of cf.

What is the chance that Kathy’s child has inherited the cystic fibrosis?

  • 1/2 1/2 = 1/4
  • 1/3  1/2 = ⅙
  • 2/3  1/4 = 1/6
  • 2/3  1/2 = 1/3

6. The occurrence of affected individuals in every generation in a family

suggests which of these traits?

  • An autosomal dominant
  • An autosomal recessive
  • Either dominant or recessive
  • Sex-linked

7. Which of the following is an example of a dihybrid cross?

  • AaBb  aabb
  • AaBb  AaBb
  • aabb  AABB
  • aabb  aabb

8. Which of the following phenotypic results are expected from a dihybrid cross?

  • 1  choose which one is correct: 1  choose which one is correct: 1  choose which one is correct: 1 ratio
  • 9  choose which one is correct: 3  choose which one is correct: 3  choose which one is correct: 1 ratio
  • All dominant for both traits
  • All recessive for both traits

9. Mendel’s law of which states that a random assortment of maternally and

paternally derived chromosomes in meiosis results in gametes that have

different combinations of these genes?

  • Particulate inheritance
  • Dominance
  • Segregation
  • Independent assortment

10. Which of the following incorrectly identifies the mode of inheritance for the

given genetic disease?

  • Distal symphalangism-dominant
  • Cystic fibrosis-recessive
  • Albinism-recessive
  • Sickle cell-dominant

11. Approximately how many human single-gene traits and illnesses are

currently known from medical reports?

  • 100
  • 1000
  • 10000
  • 100000

12. Mendel’s laws are explained by choose which one is correct:

  • Chromosome behaviour in mitosis
  • Chromosome behaviour in meiosis
  • Cytokinesis in mitosis and meiosis
  • Mendel’s laws have not been explained

13. Which genotype is normally not found in a gamete?

  • AB
  • Ab
  • aa
  • ab

14. Which of the following crosses is a test cross?

  • Unknown  AA
  • Unknown  Aa
  • Unknown  aa
  • Unknown  Unknown

15. Two phenotypically normal individuals have an affected child. What can we conclude about the parents?

  • They both carried the disease allele
  • They are not the parents of the child
  • They are affected
  • No conclusions can be drawn

16. Which geneticist has compiled a compendium of human genetic traits called

mendelian inheritance in man?

  • Gregor Mendel
  • Hermann Muller
  • Victor McKusick
  • John Hopkins

17. Relatives who have children together have a much higher risk of having

children affected by.

  • Environmental condition
  • Dominant condition
  • Recessive condition
  • Undetected condition

18. Consider a group of 100 individuals (50 couples), all of whom carry a

recessive disease allele. If 200 children were born to these couples, what

percentage of the children would, theoretically, be carriers like their parents?

  • 0
  • 25
  • 50
  • 75

19. In the cross AaBb  aabb, what percentage of the offspring are expected to

show a completely dominant phenotype?

  • 0
  • 25
  • 50
  • 100

20. Consider the cross AaBb  AaBb. If the alleles for both genes exhibit complete dominance, what genotypic ratio is expected in the resulting offspring?

  • 1  choose which one is correct: 1  choose which one is correct: 1  choose which one is correct: 1
  • 9  choose which one is correct: 3  choose which one is correct: 3  choose which one is correct: 1
  • 3  choose which one is correct: 6  choose which one is correct: 3  choose which one is correct: 1  choose which one is correct: 2  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1  choose which one is correct: 2  choose which one is correct: 4  choose which one is correct: 2  choose which one is correct: 1  choose which one is correct: 2  choose which one is correct: 1

21. Can independent assortment be demonstrated in a monohybrid cross?

  • Yes, you can observe random distribution of alleles into gametes
  • Yes, you can observe random assortment of genes into gametes
  • No, you must observe genes that are on the same chromosome
  • No, you must examine the transmission of two or more genes

22 Which rule of probability is useful in calculating the risk that certain

individuals will inherit a particular genotype?

  • Product
  • Summation
  • Additive
  • None of the above is correct

23. Achondroplasia is a dominant form of dwarfism.What is the chance of

having an unaffected child from two.

  • 0
  • 25
  • 50
  • 75

24. What chance an adult sibling of a person who is a known carrier of Tay-

Sachs disease, has of being a carrier?

  • 1/4
  • 1/2
  • 1/3
  • 2/3

25. Female and male sex cells are called choose which one is correct:

  • Hybrids
  • Alleles
  • Genotypes
  • Gametes

26. Blood group O can receives choose which one is correct:

  • A
  • B
  • AB
  • None of the above

27. When Mendel conducted his experiments, he needed to transfer pollen grains

from a male reproductive organ to a female reproductive organ in a plant.

What is this process called?

  • Cross pollination
  • Heredity
  •  Monohybrid
  • Recessive

28. Blood group A can be donated to choose which one is correct:

  • B
  • AB
  • O
  • All of the above

29. Which of the following statements is not true?

  • If an organism has two alleles for a trait that are the same, it is said to be homozygous for that trait
  • The way an organism looks and behaves is called its genotype
  • A hybrid is the offspring of two parents that have different forms of a trait
  • Dominant alleles are represented with upper-case letters

30. If Mendel had chosen more than seven traits in his plants, he might have run into some confusing results regarding choose which one is correct:

  • The phenomenon of dominance
  • The law of segregation
  • The law of independent assortment
  • All of the above

31. What is the major value in using a Punnett square?

  • Shows all gametic combinations
  • Shows genotypic ratios
  • Shows phenotypic ratios
  • Sows (A), (B) and (C)

32. A co-dominance cross between a homozygous red and a homozygous white snapdragons produces choose which one is correct:

  • Plants with 50% red and 50% white flowers
  • Plants with red flowers
  • Plants with pink flowers
  • Plants with sterile flowers

33. The branch of Biology dealing with the principles that explain the similarities between parents and their progeny and differences among individuals of a species choose which one is correct:

  • Inheritance
  • Heredity
  • Genetics
  • Variation

34. Using the symbols provided below, what is the genotype of a heterozygous tall, homozygous green pod pea plant?

  • DdYy
  • DDYY
  • DdYY
  • DDYy

35. Using the symbols provided below, what is the genotype of a heterozygous tall, heterozygous green pod pea plant?

  • DDYY
  • DdYy
  • DdYY
  • DDYy

36. A recessive gene can be expressed if the genotype is choose which one is correct:

  • Homozygous recessive
  • Homozygous dominant
  • Heterozygous
  • (B) and (C)

37. A chestnut coloured horse crossed with a white coloured horse results in a palomino coat colour. This is an example of choose which one is correct:

  • Dominant inheritance
  • Recessive inheritance
  • Codominant inheritance
  • None of the above inheritance

38. Why was Mendel fairly certain that he had a pure-bred variety when he

collected seeds from a pea plant?

  • The flower is self-pollinating in these plants
  • Peas bear a large number of “offspring”
  • Because the varieties are so distinctive
  • He maintained extremely accurate records

39. If an organism with the genotype Ww is crossed with a Ww organism, what would be the proportion of offspring that would be heterozygous?

  • 1/4
  • 1/2
  • 3/4
  • All would be heterozygous

40. Phenotype is choose which one is correct:

  • The genetic make-up of an individual
  • The same for parent and offspring
  • Not observable
  • The appearance of an individual

41. If genes are not linked, a genotype of PpRr can produce how many different kinds of gametes?

  • 1
  • 2
  • 3
  • 4

42. In humans, brown eyes (B) is dominant to blue eyes (b). A brown eyed man marries a blue eyed woman. The possible eye colours of their children are choose which one is correct:

  • All brown
  • Half brown
  • 3/4 brown, 1/4 blue
  • Not enough information is given

43. Mendel was the first biologist to choose which one is correct:

  • Study the mechanics of inheritance
  • Discover that chromosomes are responsible for inheritance
  • Use statistical methods in analyzing his results
  • All of the above

44. Mendel’s law of segregation states that choose which one is correct:

  • Two factors for the same trait separate in the production of gametes
  • Two different traits will be inherited independently of each other
  • Gametes are produced by meiosis
  • All of the above

45. If an individual has a recessive phenotype for a given trait, the genotype must be choose which one is correct:

  • Heterozygous
  • Homozygous recessive
  • Homozygous dominant
  • Either homozygous recessive or heterozygous

46. The part of DNA which controls a specific character is choose which one is correct:

  • Allele
  • Gene
  • Locus
  • Factor

47. The position of gene is choose which one is correct:

  • Gene
  • Allele
  • Factor
  • Locus

48. Variations are produced due to choose which one is correct:

  • Allele
  • Locus
  • Gene
  • Mutation

49. Partners of gene pair are choose which one is correct:

  • Allele
  • Gene
  • Locus
  • Factor

50. The form of appearance of trait is choose which one is correct:

  • Gene pool
  • Genotype
  • Phenotype
  • Mutation

51. Mendel selected pea because it is naturally choose which one is correct:

  • Cross fertilized
  • Self fertilized
  • Unisexual
  • Long generation time

52. Which is irrelevant for pea?

  • Self fertilized
  • Hermaphrodite
  • Sharply distinct trait
  • None of the above

53. True breeding variety is choose which one is correct:

  • Self fertilized
  • Cross fertilized
  • Unisexual
  • Hermaphrodite

54. Which of the followings is true breeding variety?

  • Tt
  • Rr
  • RR
  • Ss

55. The organisms produced by self cross differing in one characters are choose which one is correct:

  • True breed
  • Dihybrids
  • Monohybrids
  • Hybrid

56. The cross in which two characters are followed at the same time is called choose which one is correct:

  • Monhybrid cross
  • Reciprocal cross
  • Dihybrids cross
  • Hybrid cross

57. When round wrinkle were crossed, it gave all round. This round is choose which one is correct:

  • P1 generation
  • F1 generation
  • F2 generation
  • F3 generation

58. When tall is crossed with dwarf, F1 gives tall, it is choose which one is correct:

  • Recessive
  • Hybrid
  • Dominant
  • None of the above

59. Law of segregation suggests that each gametes has choose which one is correct:

  • TT
  • Tt
  • T
  • tt

60. The results of Mendelian F1 were all choose which one is correct:

  • RR
  • Rr
  •  rr
  • None of the above

61. The genetic complement of an individual is called choose which one is correct:

  • Mutation
  • Phenotype
  • Genotype
  • Gene pool

62. Total genes found in a population is choose which one is correct:

  • Gene pool
  • Genotype
  • Phenotype
  • Mutation

63. Match beanbag genetics with one of the followings choose which one is correct:

  • Genotype
  • Gene pool
  • Mutation
  • Phenotype

64. Match bean in beanbag with one of the followings choose which one is correct:

  • Gene pool
  • Gene
  • Phenotype
  • Allele

65. A sample population of 100 plants has number of alleles choose which one is correct:

  • 50
  • 100
  • 200
  • 400

66. Mendel laid the foundation of choose which one is correct:

  • Hereditary genetics
  • Classical genetics
  • Cytological genetics
  • Modern genetics

67. Which of the following scientists rediscovered the work of Mendel?

  • De Varies
  • Tschernimach
  • Correns
  • All of the above

68. The work of Mendel remained neglected for choose which one is correct:

  • 23 years
  • 34 years
  • 44 years
  • 54 years

69. The work of Mendel was rediscovered after how many years of his death is?

  • 12 years
  • 14 years
  • 16 years
  • 18 years

70. Which of the following characters is not studies by Mendel?

  • Pod shape
  • Seed colour
  • Plant colour
  • Flower colour

71. Which of the following Mendelian characters is mismatched?

  • Round wrinkle
  • Purple white
  • Green red
  • Yellow green

72. Mendel studied choose which one is correct:

  • Alium cepa
  • Cassia fistula
  • Pisum sativum
  • Solanum tuberosum

73. The law of segregation gives phenotypic ratio in F2 as choose which one is correct:

  • 2  choose which one is correct: 1
  • 4  choose which one is correct: 1
  • 3  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1

74. In F3 cross the round producing only round were choose which one is correct:

  • 1/4
  • 1/3
  • 1/2
  • None of the above

75. In F3 cross the 2/3 round produce choose which one is correct:

  • Round
  • Wrinkle
  • Both round and wrinkle
  • None of the above

76. In F3 cross the 2/3 round give ratio of choose which one is correct:

  • 2  choose which one is correct: 1
  • 4  choose which one is correct: 1
  • 3  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1

77. Match elementon of Mendel with one of the followings choose which one is correct:

  • Gene
  • Allele
  • Factor
  • Trait

78. Match particulate hereditary factor of Mendel with one of the followings choose which one is correct:

  • Gene
  • Factor
  • Allele
  • Trait

79. The scientist who renamed factors as genes was choose which one is correct:

  • De Varies
  • Tschernimach
  • Correns
  • Johaunsen

80. Which of the followings is homozygous?

  • Tt
  • Rr
  • RR
  • Ss

81. The trait found in 1/4 of F2 was choose which one is correct:

  • RR
  • Rr
  • rr
  • None of the above

82. The law of segregation gives genotypic ratio in F2 as choose which one is correct:

  • 2  choose which one is correct: 1
  • 4  choose which one is correct: 1
  • 3  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1

83. Punnett square gives Rr in F2 as choose which one is correct:

  • 1/4
  • 1/2
  • 3/4
  • 1/3

84. The cross used to determine the genotype is called choose which one is correct:

  • Monohybrid cross
  • Test cross
  • Dihybrid cross
  • Reciprocal cross

85. If test cross gives all dominant characters it means the parent is choose which one is correct:

  • Homozygous recessive
  • Heterozygous
  • Homozygous dominant
  • Heterozygous dominant

86. If test cross gives 50% dominant and 50% recessive characters it means the parent is choose which one is correct:

  • Homozygous recessive
  • Heterozygous
  • Homozygous dominant
  • Heterozygous dominant

87. In test cross if the parent whose genotypes is to be determined is

heterozygous then it gives choose which one is correct:

  • 1  choose which one is correct: 1
  • 3  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1
  • 1  choose which one is correct: 2

88. If an organism has TtRr genotype, then which of the following gametes does not follow law of independent assortment?

  • TR
  • Tr
  • Rr
  • Tr

89. The ratio for law of independent assortment is choose which one is correct:

  • 9  choose which one is correct: 3  choose which one is correct: 1
  • 3  choose which one is correct: 1
  • 1  choose which one is correct: 2  choose which one is correct: 1
  • 9  choose which one is correct: 3  choose which one is correct: 3  choose which one is correct: 1

90. 9  choose which one is correct: 3  choose which one is correct: 3  choose which one is correct: 1 ratio is given by choose which one is correct:

  • P1
  • F1
  • F3
  • F4

91. Blood group MN has antigen choose which one is correct:

  • M
  • N
  • MN
  • None of the above

92. If a man with blood group M marries with woman N, the offspring will be choose which one is correct:

  • All M
  • All N
  • All MN
  • Both M and N

93. The more phenotypic tissue than genotypic ratio is choose which one is correct:

  • Complete dominance
  • Incomplete dominance
  • Codominance
  • Over dominance

94. ABO blood group system was discovered by choose which one is correct:

  • Carl Correns
  • Landsteiner
  • T.H. Morgan
  • Mendel

95. The blood group without antigen is choose which one is correct:

  • A
  • AB
  • B
  • O

96. The blood group without antibody is choose which one is correct:

  • A
  • AB
  • B
  • O

97. The genetic basis of ABO blood group system was discovered by choose which one is correct:

  • Carl Correns
  • Landsteiner
  • T.H. Morgan
  • Bernstein

98. Which of the followings is not multiple allele?

  • ABO blood group
  • Human height
  • MN blood group
  • Skin colour

99. In AB blood group IAI B is choose which one is correct:

  • Complete dominance
  • Incomplete dominance
  • Codominance
  • Over dominance

100. The antiserum contains choose which one is correct:

  • Antibody
  • Antigen
  • Albumin
  • None of the above

101. Who for the first time found white eye mutation in Drosophila?

  • Morgan
  • Bridges
  • Correns
  • De Varies

102. Which of the following traits is not sex-linked recessive?

  • Haemophilia
  • Colour blindness
  • tfm syndrom
  • Hypophosphatemic ricket

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