Question

In AGCT of DNA, hydrogen bonds and base pairing occur between

• A. A—C, G—T
• B. All of the above
• C. A—T, C—G
• D. A—G, C—T

Answer 1

The correct option is C A—T, C—G

Base pairing in DNA
DNA consists of 4 types of nitrogenous bases which are adenine, guanine, cytosine and thymine. These bases project towards the inner side of the DNA double helix and form pairs with the complementary bases on the opposite strand. A purine (adenine or guanine) always pairs with a pyrimidine (cytosine or thymine).

A-T pair
Adenine (A) pairs with thymine (T) with the help of 2 hydrogen bonds.


G-C pair
Guanine (G) pairs with cytosine with the help of 3 hydrogen bonds.

Final answer
(C) A—T, C—G