DNA extracted from a bacterium was identified as having a guanine content of 14%.From this information determine the percentage of A.
A) 14%
B) 28%
C) 36%
D) 78%
E) There is not enough information to determine this.

Question

Quizplus · Accepted Answer

Since DNA is a double-stranded helix and guanine pairs with cytosine (which makes up the other 36%), adenine must pair with thymine in the complementary strand that is not given. Therefore, the percentage of A is the same as the percentage of T, which is 36%.

DNA Extracted from a Bacterium Was Identified as Having a Guanine