Question

If the amount of A is 30% in a strand of DNA, what will be the % of G?

Answer 1

From Wikipedia: "Chargaff's rules state that DNA from any cell of any organisms should have a 1:1 ratio of pyrimidine and purine bases and, more specifically, that the amount of guanine should be equal to cytosine and the amount of adenine should be equal to thymine."

A pairs with T and G pairs with C.

So, the amount of thymine in the DNA will equal the amount adenine in the DNA, which will also be 30%. And the amount of guanine and cytosine will make up the remaining amount of DNA, which is 40%. Since guanine and cytosine just be in equal amounts, the answer is 20%.

Answer 2

Auto spell mistake, last sentence should read, Since guanine and cytosine must be in equal amounts, the answer is 20%. "