Thymine makes up 23% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine?

Question

Thymine makes up 23% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine?

 23% 27% 46% 54%

Answer 1

DNA bases bond in pairs with Thymine to Adenine and Guanine to Cytosine. For every one Thymine there will be one Adenine.

So, 23% Thymine would mean that there is also 23% Guanine.

The remaining bases would have to equal 100% - (23% + 23%) = 54%

Guanine would equal 54%/2 or 27%.