Number of hydrogen bond formed between adenine and thymine to connect each other is/are ______
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 2
In the DNA double helix the two strands are held together by hydrogen bonds between complementary bases: adenine pairs only with thymine, and guanine only with cytosine. Adenine and thymine line up two donor–acceptor pairs, so they are joined by 2 hydrogen bonds (A=T); guanine and cytosine are joined by three (G≡C).
NCERT (2026-27 edition):
Structure of Nucleic Acids – “… The two strands are complementary to each other because the hydrogen bonds are formed between specific pairs of bases. Adenine forms hydrogen bonds with thymine whereas cytosine forms hydrogen bonds with guanine.”