Match List I with List II:List I List II A. Down's syndrome I. 11th chromosome B. α-Thalassemia II. 'X' chromosome C. β-Thalassemia III. 21st chromosome D. Klinefelter's syndrome IV. 16th chromosome
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| A. Down's syndrome | I. 11th chromosome |
| B. α-Thalassemia | II. 'X' chromosome |
| C. β-Thalassemia | III. 21st chromosome |
| D. Klinefelter's syndrome | IV. 16th chromosome |
Answer: (B) A-III, B-IV, C-I, D-II. Answer: (B) A-III, B-IV, C-I, D-II Solution: Down's syndrome is caused by trisomy of chromosome 21 (A-III).
- A.A-II, B-III, C-IV, D-I
- B.A-III, B-IV, C-I, D-II✓
- C.A-IV, B-I, C-II, D-III
- D.A-I, B-II, C-III, D-IV
Correct Answer
(B) A-III, B-IV, C-I, D-II
Solution & Explanation
Answer: (B) A-III, B-IV, C-I, D-II Solution: Down's syndrome is caused by trisomy of chromosome 21 (A-III). Alpha-thalassemia is controlled by genes (HBA1, HBA2) on chromosome 16 (B-IV). Beta-thalassemia is controlled by the HBB gene on chromosome 11 (C-I). Klinefelter's syndrome arises from an extra X chromosome giving karyotype 47,XXY (D-II). This matching gives option (b). NCERT Reference: NCERT Class XII, Ch 4, p.75, lines 27-31: "α Thalassemia is controlled by two closely linked genes HBA1 and HBA2 on chromosome 16 of each parent ... While β Thalassemia is controlled by a single gene HBB on chromosome 11 of each parent"