Question

The number of hydrogen bonds between adenine and thymine is _____.

Hint:

{A--T = 2 bonds, G--C = 3 bonds} Remember: AT is weaker than GC due to fewer hydrogen bonds.

Answer 1

Concept: DNA consists of two polynucleotide strands held together by hydrogen bonds between complementary nitrogenous bases. The pairing follows Chargaff’s base pairing rule:

• Adenine (A) pairs with Thymine (T)
• Guanine (G) pairs with Cytosine (C)

Each base pair is stabilized by a specific number of hydrogen bonds, which contribute to the stability of the DNA double helix.
Explanation: Adenine and thymine form two hydrogen bonds between them. In contrast, guanine and cytosine form three hydrogen bonds, making the G--C pair more stable than the A--T pair. Thus, the number of hydrogen bonds between adenine and thymine is 2.