Question

If percentage of cytosine is 18%, then percentage of thymine will be

• A. 32%
• B. 64%
• C. 36%
• D. 23%.

Answer 1

The correct option is A 32%

To figure out the percentage of thymine, you must first determine the percentage of guanine, which is quite simple: guanine (because it is the complementary base pair of cytosine) is equal to cytosine; therefore, there is 18% of guanine as well. Now to find thymine percentage, we initiate Chargaff’s Rule: [A]+[G]=[C]+[T]. Hence, we can deduce the proportion of G:C as 36%, which we then subtract from 100%, leaving us with 64%. Because adenine and thymine are complementary base pairs, we now have the answer to the amount of thymine in this DNA sequence: 32%.

So the correct option is '32%'.