A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
A)120 adenine and 120 uracil molecules.
B)120 thymine and 120 adenine molecules.
C)120 cytosine and 120 thymine molecules.
D)240 adenine and 240 cytosine molecules.
E)240 guanine and 240 thymine molecules.

Question

Quizplus · Accepted Answer

In a double-stranded DNA molecule, the number of purines (adenine and guanine) equals the number of pyrimidines (thymine and cytosine). Option B, with 120 adenine (a purine) and 120 thymine (a pyrimidine), maintains this balance.

A Double-Stranded DNA Molecule Contains a Total of 120 Purines