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

Number of Hydrogen Bonds Between Adenine and Thymine:

The number of hydrogen bonds formed between adenine (A) and thymine (T) is two (2).

Detailed Explanation:
In the structure of DNA (Deoxyribonucleic Acid), nitrogenous bases pair with each other in a specific and complementary manner. According to Chargaff’s rule, adenine always pairs with thymine, and guanine always pairs with cytosine.

The base pairing occurs due to the formation of hydrogen bonds between complementary bases. These hydrogen bonds hold the two strands of DNA together in a double helix structure.

– Adenine (A) pairs with Thymine (T) through two hydrogen bonds.
– Guanine (G) pairs with Cytosine (C) through three hydrogen bonds.

The presence of two hydrogen bonds between A and T makes this pair slightly less strong compared to the G–C pair, which has three hydrogen bonds and provides greater stability to the DNA molecule.

Importance:
These hydrogen bonds are weak individually but collectively strong enough to maintain the stability of DNA. At the same time, they are weak enough to allow the DNA strands to separate during replication and transcription.

Conclusion:
Therefore, adenine and thymine are connected by two hydrogen bonds in the DNA molecule.