NEET 2020 · BiologyPrevious Year Question
Which of the following statements is correct? a. Adenine pairs with thymine through three H-bonds b. Adenine does not pair with thymine c. Adenine pairs with thymine through two H-bonds d. Adenine pairs with thymine through one H-bond
Answer: (C) Adenine pairs with thymine through two H-bonds. Answer: (C) Adenine pairs with thymine through two H-bonds.
- A.Adenine pairs with thymine through three H-bonds
- B.Adenine does not pair with thymine
- C.Adenine pairs with thymine through two H-bonds✓
- D.Adenine pairs with thymine through one H-bond
Correct Answer
(C) Adenine pairs with thymine through two H-bonds
Solution & Explanation
Answer: (C) Adenine pairs with thymine through two H-bonds. In the double helix adenine forms two hydrogen bonds with thymine (while guanine forms three with cytosine). NCERT Ch 5, p.81, lines 37-39: "Adenine forms two hydrogen bonds with Thymine from opposite strand and vice-versa."
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