Question

If there is 20% adenine in DNA, the percentage of guanine will be

• A. 20%
• B. 40%
• C. 10%
• D. None of the above

Answer 1

The correct option is D None of the above

As per Chargaff's rule in a molecule of DNA, the amount of adenine is equal to thymine and amount of guanine is equal to cytosine. So if the percentage of adenine is 20 so the percentage of thymine will be 20 and the percentage of cytosine will be 80 percent, so, the amount of guanine should also be 80 percent. Because, according to this model, adenine always base pairs with thymine with the help of two hydrogen bonds and guanine base pairs with cytosine with the help of a triple hydrogen bond.

So, the correct answer is option D.