Question

Assertion (A): The two chains of a DNA double helix are anti-parallel.

Reason (R): Nucleotides in the each helix are joined together by phosphodiester bonds.

Options

• Both assertion (A) and reason (R) are true, and reason is the correct explanation of assertion.

• Both assertion (A) and reason (R) are true, but reason is not the correct explanation of assertion.

• Assertion (A) is true but reason (R) is false.

• Both assertion (A) and reason (R) are false.

Answer 1

Both assertion (A) and reason (R) are true, but reason is not the correct explanation of assertion.

Explanation:

Both statements are true, but phosphodiester bonds link nucleotides within each strand; they do not explain why the two strands run in opposite directions. The strands are antiparallel because their polarities are opposite.