Question

If a species contains 23% adenine in its DNA, what is the percentage of guanine it would contain?

• A. 23%
• B. 46%
• C. 44%
• D. 27%

Answer 1

The correct option is D 27%

According to Chargaff's rule, adenine always pairs with thymine and cytosine always with guanine. Therefore the percentage of A and T must be approximately equal to the G and C. So in this we have 23% adenine then thymine also be equal to 23%. So A+T = 46%. Remaining is 54% must be between G and C. Divide 54 by 2 so we get 27 %.

So, the correct option is '27%'.