1. Genetic disorders are caused due to

A. Environmental factors B. Infectious agents C. Changes in genes or chromosomes D. Hormonal imbalance

✅ Answer: C

📘 Explanation: Genetic disorders result from gene or chromosomal abnormalities.

2. Mendelian disorders are

A. Polygenic B. Caused by multiple chromosomes C. Single-gene disorders D. Environmental disorders

✅ Answer: C

3. Which of the following is a Mendelian disorder?

A. Down syndrome B. Turner syndrome C. Sickle cell anaemia D. Klinefelter syndrome

✅ Answer: C

4. Sickle cell anaemia is inherited as

A. Autosomal dominant B. Autosomal recessive C. X-linked dominant D. X-linked recessive

✅ Answer: B

5. The mutation responsible for sickle cell anaemia is

A. Frameshift mutation B. Nonsense mutation C. Point mutation D. Deletion mutation

✅ Answer: C

6. In sickle cell anaemia, which amino acid is replaced?

A. Glycine B. Alanine C. Valine D. Leucine

✅ Answer: C

7. Phenylketonuria is caused due to deficiency of

A. Insulin B. Phenylalanine hydroxylase C. Tyrosinase D. Amylase ✅ Answer: B

8. Phenylketonuria is inherited as

A. Autosomal dominant B. X-linked recessive C. Autosomal recessive D. Y-linked

✅ Answer: C

9. Accumulation of phenylalanine affects

A. Liver B. Kidney C. Brain D. Heart

✅ Answer: C

10. Huntington’s disease is

A. Autosomal recessive B. X-linked recessive C. Autosomal dominant D. Y-linked

✅ Answer: C

11. Huntington’s disease generally appears

A. At birth B. During childhood C. In adolescence D. In adulthood ✅ Answer: D

12. Haemophilia is a disorder related to

A. Blood clotting B. Oxygen transport C. Immunity D. Digestion

✅ Answer: A

13. Haemophilia is inherited as

A. Autosomal dominant B. Autosomal recessive C. X-linked recessive D. X-linked dominant

✅ Answer: C

14. Haemophilia affects mostly

A. Females B. Males C. Both equally D. Newborns only

✅ Answer: B

15. Colour blindness is a

A. Autosomal disorder B. Sex-linked disorder C. Chromosomal disorder D. Polygenic disorder

✅ Answer: B

16. Which chromosome carries genes for colour blindness?

A. Chromosome 21 B. Y chromosome C. X chromosome D. Autosome

✅ Answer: C

17. Chromosomal disorders occur due to

A. Single gene mutation B. Environmental factors C. Abnormal chromosome number or structure D. Enzyme deficiency

✅ Answer: C

18. Gain or loss of one chromosome is called

A. Polyploidy B. Euploidy C. Aneuploidy D. Diploidy

✅ Answer: C

19. Down syndrome is caused by A. Monosomy X B. Trisomy 21 C. XXY condition D. Deletion of chromosome 5

✅ Answer: B

20. The chromosome number in Down syndrome is

A. 45 B. 46 C. 47 D. 48

✅ Answer: C

21. Turner syndrome is represented by

A. XX B. XO C. XXY D. XYY

✅ Answer: B

22. Turner syndrome affects

A. Only males B. Only females C. Both sexes D. Infants only

✅ Answer: B

23. Klinefelter syndrome has the karyotype

A. XO B. XX C. XXY D. XYY

✅ Answer: C

24. Klinefelter syndrome results in

A. Sterile females B. Sterile males C. Normal males D. Normal females

✅ Answer: B

25. Cri-du-chat syndrome is due to

A. Trisomy 21 B. Deletion of chromosome 5 C. Monosomy X D. Duplication of chromosome 21

✅ Answer: B

26. The characteristic cry in Cri-du-chat syndrome resembles

A. Dog B. Cow C. Cat D. Goat

✅ Answer: C

27. Nondisjunction occurs during

A. Transcription B. Translation C. Cell division D. DNA replication

✅ Answer: C

28. Which disorder is caused by nondisjunction?

A. Sickle cell anaemia B. Haemophilia C. Down syndrome D. PKU

✅ Answer: C

29. Structural chromosomal abnormalities include

A. Polyploidy B. Aneuploidy C. Deletion and duplication D. Trisomy

✅ Answer: C

30. Which disorder is X-linked recessive?

A. Down syndrome B. Sickle cell anaemia C. Haemophilia D. PKU

✅ Answer: C

31. Why are males more affected in X-linked disorders?

A. Larger X chromosome B. Single X chromosome C. Presence of Y chromosome D. Dominant genes

✅ Answer: B

32. Autosomal recessive disorders appear when

A. One allele is defective B. Both alleles are defective C. Gene is on X chromosome D. Gene is on Y chromosome

✅ Answer: B

33. Which disorder shows delayed onset?

A. PKU B. Haemophilia C. Huntington’s disease D. Colour blindness

✅ Answer: C

34. A carrier female for haemophilia is

A. Diseased B. Normal but transmits gene C. Always affected D. Sterile

✅ Answer: B

35. The study of genetic disorders helps in

A. Evolution only B. Disease diagnosis C. Genetic counseling D. All of these

✅ Answer: D

36. Chromosomal disorders do NOT follow

A. Mendelian inheritance B. Law of segregation C. Law of dominance D. Independent assortment

✅ Answer: A

37. Which disorder affects intelligence most severely if untreated?

A. PKU B. Haemophilia C. Colour blindness D. Turner syndrome

✅ Answer: A

38. The extra chromosome in Down syndrome is

A. X B. Y C. 21 D. 18

✅ Answer: C

39. Which genetic disorder affects blood oxygen transport?

A. PKU B. Sickle cell anaemia C. Haemophilia D. Colour blindness

✅ Answer: B

40. Turner syndrome individuals are

A. Fertile B. Normal height C. Infertile D. Hyper fertile

✅ Answer: C

41. Which disorder shows gynaecomastia?

A. Turner syndrome B. Down syndrome C. Klinefelter syndrome D. PKU

✅ Answer: C

42. Autosomal dominant disorder requires

A. Both alleles defective B. One defective allele C. X chromosome D. Y chromosome

✅ Answer: B

43. Which disorder is due to enzyme deficiency?

A. Down syndrome B. Turner syndrome C. PKU D. Klinefelter syndrome

✅ Answer: C

44. Which disorder is related to vision?

A. PKU B. Haemophilia C. Colour blindness D. Down syndrome

✅ Answer: C

45. The most common chromosomal disorder in humans is

A. Turner syndrome B. Klinefelter syndrome C. Down syndrome D. Cri-du-chat syndrome

✅ Answer: C

46. Gene mutation causes

A. Chromosomal disorders B. Mendelian disorders C. Polyploidy D. Aneuploidy

✅ Answer: B

47. Which disorder is inherited through sex chromosomes?

A. PKU B. Sickle cell anaemia C. Colour blindness D. Down syndrome

✅ Answer: C

48. The study of inheritance of disorders is useful in

A. Medical diagnosis B. Prenatal screening C. Genetic counseling D. All of these

✅ Answer: D

49. Which disorder affects only females?

A. Klinefelter syndrome B. Turner syndrome C. Haemophilia D. PKU

✅ Answer: B

50. Genetic counseling helps to

A. Cure genetic disorders B. Prevent inheritance of disorders C. Educate families about risks D. Remove mutations

✅ Answer: C

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Concepts:Sex Determination