An organism's genomic DNA is analyzed and found to contain 22% thymine. What percentage of that organism's DNA is guanine?
A)22%
B)28%
C)44%
D)56%
E)78%

Question

Quizplus · Accepted Answer

In DNA, there is an equal amount of thymine and adenine and an equal amount of guanine and cytosine. Therefore, if the organism's DNA contains 22% thymine, it must also contain 22% adenine. Together, these two nucleotides account for 44% of the DNA. The remaining 56% must be split evenly between guanine and cytosine, so the percentage of guanine is also 28%.

An Organism's Genomic DNA Is Analyzed and Found to Contain