Class 12 Biology MCQs Chapter – 5
41. Polygenic inheritance in plants like tobacco was first studied by:
( A ) Davenport
( B ) Nilsson-Ehle
( C ) Kolreuter
( D ) Galton
ANS-( C )
42. A recessive trait in Garden pea is
( A ) wrinkled seeds
( B ) tall stem
( C ) round seeds
( D ) coloured seeds coats
ANS-( A )
43. In complementary genes, the dihybrid ratio of 9: 3: 3: 1 is modified into
( A ) 9: 7
( B ) 12: 3: 1
( C ) 15: 1
( D ) 13: 3
ANS-( A )
44. Which blood groups are common in Man & Apes but absent in Monkey?
( A ) A and O
( B ) A and B
( C ) AB and O
( D ) B and AB
ANS-( B )
45. Number of barr bodies present in Turner’s syndrome is:
( A ) 0
( B ) 1
( C ) 2
( D ) 8
ANS-( A )
46. In an individual haploid number is 10. Its tetrasomic number will be:
( A ) 40
( B ) 14
( C ) 22
( D ) 44
ANS-( C )
47. A male grass hopper will have a sex complement of:
( A ) XY
( B ) XX
( C ) XO
( D ) YO
ANS-( C )
48. Individuals with blood group A has:
( A ) Antigen A, antibody B
( B ) Antigen B, antibody A
( C ) Antigen A, antibody b
( D ) Antigen A, no antibody
ANS-( C )
49. Phenomenon of one gene controlling several phenotypes is:
( A ) Epistasis
( B ) Pleiotropism
( C ) Co-dominance
( D ) Multiple allelism
ANS-( B )
50. The monohybrid genotypic ratio 1: 2 : 1 in F2 generation indicates:
( A ) Segregation
( B ) Independent assortment
( C ) Dominance
( D ) Incomplete dominance
ANS-( A )
51. Genes present on same locus having different expressions are called
( A ) Multiple allele
( B ) Polygene
( C ) Oncogene
( D ) Codominant gene
ANS-( A )
52. The human chromosome with highest and least number of genes are
( A ) Chromosome 21 and Y
( B ) Chromosome 1 and X
( C ) Chromosome 1 and Y
( D ) Chromosome X and Y
ANS-( C )
53. Sickle cell anaemia shows-
( A ) Epistrasis
( B ) Co – dominance
( C ) Pleiotropy
( D ) Incomplete dominance
ANS-( C )
54. The trisomy of 21st chromosome causes …
( A ) Klinefelter’s syndrome
( B ) Turner’s syndrome
( C ) Sickle cell anaemia
( D ) Down’s syndrome
ANS-( D )
55. A normal vision female whose father is colour – blind marries normal vision male What would be the probability of her sons and daughters to be colour blind ?
( A ) 25 % sons colour blind and all daughters with phenotypically normal vision
( B ) 50 % sons colour blind and 50 % daughter mormal
( C ) 50 % sons colour blind and 50 % daughter colour blind .
( D ) All sons normal and 50 % colour blind daughter
ANS-( B )
56. A child with blood group o ‘ has B blood group type father then the father has geno type of —
( A ) lOIO
( B ) IOIB
( C ) IBIB
( D ) IA IA
ANS-( B )
57. Lactose ( Lac ) operon is regulated by :
( A ) Lac repressor only
( B ) Lac repressor and CAP – CAMP complex
( C ) Lac repressor and c – GMP complex
( D ) CAP CAMP and CAP GMP complex
ANS-( B )
58. Mendel’s law of segregation applicable to :
( A ) Monohybrid cross
( B ) Hybrid cross
( C ) Hybrid but Monohybrid cross
( D ) Homologous pairs between cromozome
ANS-( D )
59. The phenotypic ratio for F2 generation in Incomplete dominance is
( A ) 3 : 1
( B ) 2 : 2
( C ) 1 : 2 : 1
( D ) None of these
ANS-( C )
60. Sickle – cell anemia is related to which type of disease ?
( A ) Sex linked disease
( B ) Autosomal linked disease
( C ) Deficiency disease
( D ) Metabolic disease
ANS-( B )
