Question

Choose the correct answer from each of the four options given below:
The hydrogen bonds between adenine and thymine of a DNA double-strand are

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

The correct option is B

Two

Hint: There are four types of nitrogenous bases namely- Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).

The correct option is B:

Explanation of correct option:

1. Each DNA strand is formed of alternate phosphate and sugar radicals.
2. Nitrogenous bases are attached at right angles to sugar radicals.
3. There are two DNA strands, so the two nitrogen bases come to lie opposite each other and develop hydrogen bonds.

Thus, there are two hydrogen bonds between adenine and thymine.