question_answer

Which of the following is correct about H-bonding in nucleotide?                              [AIPMT 2001]

A) A-T, G-C

B) A-G, T-C

C) G-T, A-C

D) A-A, T-T

Correct Answer: A

Solution :

[a] The structure of DNA molecule is a double helicle structure. In this structure double helix are made up of polynucleotide chains which are held together by H-bonds. In these helixes the adenine base is linked with thymine (T) by two H-bonds and guanine (G) is linked with cytocine by three H-bonds as A=T, and G C.