Sex Determination and Genetic Disorders
Multiple Choice Questions and Answers
1. A haemophilic man marries a normal homozygous women. What are the chances that their son will be haemophiliac?
(a) 100%
(b) 75%
(c) 50
(c) none
Answer: (c) none
2. A colour blind man marries a woman who is carrier of the trait; it is expected that
(a) all sons are normal and daughters are colour blind
(b) all their children are colour blind
(c) all daughters are normal and all sons colour blind
(d) some sons and some daughters are colour blind
Answer: (d) some sons and some daughters are colour blind
3. colour blind man has a normal brother and colour blind sister. What should be the phenotypes of the parents?
(a) father normal, mother colour blind
(b) father colour blind, mother carrier
(c) both colour blind
(d) both normal
Answer: (b) father colour blind, mother carrier
4. If males with the disease always die, how is it that the trait still remains in the population?
(a) some males carry it in the recessive condition and thus transmit it.
(b) one-half of the male and female children inherit and act as carriers
(c) mothers pass it on to one half of their daughters who act as carriers
(d) this occurs as a result of mutations
Answer: (c) mothers pass it on to one half of their daughters who act as carriers
5. A family of five daughters only is expecting sixth issue. The chance of its being a son is
(a) zero
(b) 25%
(c) 50%
(d) 100%
Answer: (c) 50%
6. Haemophilia is more common in males because it is a
(a) recessive character carried by Y chromosome
(b) dominant character carried by Y chromosome
(c) dominant trait carried by X chromosome
(d) recessive trait carried by X chromosome
Answer: (a) recessive character carried by Y chromosome
7. Women rarely experience sex-linked defects because they must be
(a) homozygous
(b) carrier
(c) heterozygous
(d) develop immunity
Answer: (a) homozygous
8. A single recessive trait which can express its effect should occur on
(a) any autosome
(b) any chromosome
(c) X chromosome of female
(d) X chromosome of male
Answer: (d) X chromosome of male
9. Recessive characters are expressed
(a) only when they are present on X chromosome of male
(b) only when they are present on X chromosome of female
(c) on any autosome
(d) on both the chromosomes of female
Answer: (a) only when they are present on X chromosome of male
10. An abnormal human male phenotype involving an extra X chromosome is a case of
(a) down syndrome
(b) intersex
(c) Edward syndrome
(d) Klinefelter syndrome
Answer: (d) Klinefelter syndrome
11. The chromosomal basis of sex determination was discovered in
(a) Melandrium
(b) Rumex
(c) Sphaerocarpus
(d) Coccinea
Answer: (a) Melandrium
12. Male XX and female XY sometimes occur due to
(a) deletion
(b) transfer of segments in X and Y chromosomes
(c) aneuploidy
(d) hormonal imbalance
Answer: (b) transfer of segments in X and Y chromosomes
13. Which of the following is the example of sex linked disease?
(a) AIDS
(b) Colour blindness
(c) Syphilis
(d) Gonorrhoea
Answer: (b) Colour blindness
14. A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is
(a) sex linked dominant
(b) sex linked recessive
(c) sex limited character
(d) autosomal dominant
Answer: (a) sex linked dominant
15. In Drosophila, the sex is determined by
(a) the ratio of number of X-chromosomes to the sets of autosomes
(b) X and Y chromosomes
(c) the ratio of pairs of X-chromosomes to the pairs of autosomes
(d) whether the egg is fertilized or develops parthenogenetically
Answer: (a) the ratio of number of X-chromosomes to the sets of autosomes
16. The recessive genes located on X chromosome in humans are always
(a) Expressed in females
(b) Lethal
(c) Sub Lethal
(d) Expressed in males
Answer: (d) Expressed in males
17. In normal woman, whose father was colour blind is married to a normal man. The sons would be
(a) all colour-blind
(b) 75% colour-blind
(c) 50% colour-blind
(d) all normal
Answer: (c) 50% colour-blind
18. In men sex linked characters are mainly transmitted through
(a) autosomes
(b) X chromosome
(c) Y chromosome
(d) all of them
Answer: (b) X chromosome
19. Unfertilized egg of human contains
(a) one Y chromosome
(b) X and Y chromosome
(c) XX chromosome
(d) one X chromosome
Answer: (d) one X chromosome
20. A colour blind person cannot distinguish the colour
(a) green-blue
(b) red-blue
(c) green-red
(d) none
Answer: (c) green-red
21. A male child in human will have chromosomes
(a) XO
(b) XXY
(c) XY
(d) XX
Answer: (c) XY
22. A son will be born when
(a) mother gets more nutritive food during pregnancy
(b) father is more powerful than the mother
(c) foetus has XY chromosomes
(d) foetus has XX chromosomes
Answer: (c) foetus has XY chromosomes
23. 242Ovum of human female has how many chromosomes
(a) 22 pair autosomes and one sex chromosome
(b) 22 autosomes and one sex chromosome
(c) 44 autosomes and one pair sex chromosome
(d) 22 pair autosomes
Answer: (b) 22 autosomes and one sex chromosome
24. Genes for colour blindness in man are located on
(a) Y chromosome
(b) X chromosome
(c) both X or Y chromosome
(d) either X or Y chromosome
Answer: (b) X chromosome
25. In Down’s syndrome (Mongolism) each cell has how many chromosomes
(a) 21st pair having one less
(b) 23rd pair with one less
(c) 45
(d) 47
Answer: (d) 47
26. Which is genetically dominant trait in man:
(a) Albinism
(b) Haemophilia
(c) Rh- positive
(d) Colour blindness
Answer: (c) Rh- positive
27. The genotype of man having sexual character of female is
(a) XXX
(b) XO
(c) XYY
(d) XXY
Answer: (d) XXY
28. Turner’s syndrome has the following chromosome arrangement
(a) XX
(b) XYY
(c) XY
(d) XO
Answer: (d) XO
29. Arrangement of sex chromosome in klinefelter’s syndrome is
(a) XX
(b) XY
(c) XXY
(d) XO
Answer: (d) XO
30. Allele is dominant when it is
(a) linked with autosomes
(b) linked with Y chromosomes
(c) linked with any chromosomes
(d) linked with X chromosome
Answer: (c) linked with any chromosomes
31. Somatic cells of a human milk contain single barr body, the genetic composition of the person would be
(a) XYY
(b) XXY
(c) XO
(d) XXXY
Answer: (b) XXY
32. 3When 44 + X X Y male condition occurs in human, the person suffers from
(a) Paton’s syndrome
(b) Down’s syndrome
(c) Turner’s syndrome
(d) Klinefelter’s syndrome
Answer: (b) Down’s syndrome
33. Sickle cell anaemia occurs due to
(a) change in glutamic acid from valine involving b-chain
(b) change in valine from glutamic acid involving b-chain
(c) change in valine from glutamic acid involving a-chain
(d) any change in b-chain
Answer: (c) change in valine from glutamic acid involving a-chain
34. In newborn baby haemophilic diseases is caused by
(a) incompatibility of ABO
(b) AB incompatibility
(c) Rh incompatibility
(d) O incompatibility
Answer: (c) Rh incompatibility
35. Genetic identity of human male is determined by
(a) cell organelles
(b) autosome
(c) nucleolus
(d) sex chromosome
Answer: (d) sex chromosome
36. Absence of which factor causes haemophilia?
(a) factor Rh
(b) factor I
(c) factor II
(d) factor VIII
Answer: (d) factor VIII
37. Which one of the following conditions though harmful in itself, is also potential saviour from a mosquito borne infectious disease?
(a) Thalassemia
(b) Sickle cell anaemia
(c) Pernicious anaemia
(d) Leukemia
Answer: (b) Sickle cell anaemia
38. Pattern baldness, moustaches and beard in human males are examples of
(a) sex linked traits
(b) sex limited traits
(c) sex differentiating traits
(d) sex determining traits
Answer: (b) sex limited traits
39. Recessive gene present on one X chromosome of humans will be
(a) Lethal
(b) Sublethal
(c) Expressed in males
(d) Expressed in females
Answer: (c) Expressed in males
40. Phenylketonuria is genetic disorder caused by a defect in metabolism of
(a) fatty acids
(b) polysaccharides
(c) amino acids
(d) vitamins
Answer: (c) amino acids
41. Amino acid substituted in sickle cell anaemia is
(a) glutamic acid for valine in alpha chain
(b) glutamic acid for value in beta chain
(c) valine for glutamic acid in alpha chain
(d) valine for glutamic acid in beta chain
Answer: (a) glutamic acid for valine in alpha chain
42. Which one is not a hereditary disease?
(a) cystic fibrosis
(b) cretinism
(c) thalassaemia
(d) haemophilia
Answer: (b) cretinism
43. Phenylketoneuria, Huntington’s disease and Sickle cell anaemia are caused by disorders associated with chromosomes
(a) 7, 11 and 12
(b) 12, 4 and 11
(c) 11,4 and 12
(d) 7, 12 and 11
Answer: (b) 12, 4 and 11
44. Sex chromosomes of a bird female bird are
(a) XO
(b) ZZ
(c) ZW
(d) XX
Answer: (c) ZW
45. A man suffering from recessive X linked disease marries a normal women. In the progeny
(a) all sons are normal
(b) all daughters are diseased
(c) all sons are diseased
(d) none of the above
Answer: (a) all sons are normal
46. Down’s syndrome is associated with trisomy of chromosome number
(a) 20
(b) 21
(c) 22
(d) 23
Answer: (b) 21
47. The syndrome in humans that in which individual’s somatic cells contain the three sex chromosomes XXY is called
(a) Klinefelter’s syndrome
(b) Turner’s syndrome
(c) Down’s syndrome
(d) Super female
Answer: (a) Klinefelter’s syndrome
48. The hereditary disease in which the urine of a person turns black on exposure to air due to the presence of homogenistic acid is known as
(a) Ketoneuria
(b) Phenylketonuria
(c) Haematuria
(d) Alkaptonuria
Answer: (d) Alkaptonuria
49. Which is correct for Turner’s syndrome?
(a) it is a case of monosomy
(b) it causes sterility in females
(c) absence of bar body
(d) all of the above
Answer: (d) all of the above
50. Haemophilia is related to which of the following?
(a) colour blindness
(b) polio
(c) cataract
(d) tumor
Answer: (a) colour blindness