Question

Please help me to answer this: One DNA chain of a DNA double helix contains 18% A, 35% T, 28% C, and 21% G. What is the composition of the complementary DNA?

a. %A: _____________

b. %T: _____________

c. %C: _____________

d. %G: _____________

Answer 1

According to Chargaff rule

A always base pair with T

G always base pair with C

Hence

One DNA chain of a DNA double helix contains 18% A then in other strand it will base pair with T

hence %T = 18

One DNA chain of a DNA double helix contains 35% T then in other strand it will base pair with A

hence %A = 35

One DNA chain of a DNA double helix contains 28% C then in other strand it will base pair with G

hence %G = 28

One DNA chain of a DNA double helix contains 21% G then in other strand it will base pair with C

hence %C = 21