A certain DNA sample is found to have a makeup consisting of 22% thymine. Use Chargaff’s rules to fill in the percentages for the other three nitrogenous bases.

Adenine = 22%

Guanine = 28%

Cytosine = 28%

Explanation:

According to Chargaff rule, the amount of adenine in a double-stranded DNA is equal to the amount of thymine. This is due to the fact that adenine and thymine bases are complementary and form base pairs.

Likewise, the amount of guanine in a double-stranded DNA is equal to the amount of cytosine since guanine pairs with cytosine.

Given that percentage of thymine in a DNA sample = 22%

Percentage of adenine = 22%

Total percentage of adenine and thymine = 22 + 22 = 44%

Percentage total of guanine and cytosine bases = 100-44 = 56%

Percentage of guanine base in the DNA = 56 / 2 = 28%

Percentage of cytosine base in the DNA = 28%