If a double-stranded DNA sample were composed of 10 percent thymine, what would be the percentage of guanine?
A) 10
B) 20
C) 40
D) 80
E) It is impossible to tell from the information given.

Question

Quizplus · Accepted Answer

In double-stranded DNA, the percentage of guanine must be equal to the percentage of cytosine, and the percentage of thymine must be equal to the percentage of adenine. Therefore, if the sample is composed of 10 percent thymine, then it must be composed of 40 percent guanine (since guanine and cytosine together make up 80 percent of the nucleotides, and 50 percent of that should be guanine).

If a Double-Stranded DNA Sample Were Composed of 10 Percent