A student analyzed a viral genome and found that the genome had the following nucleotide composition.

• 28% adenine
• 20% thymine
• 35% cytosine
• 17% guanine

Which of the following best describes the structure of the viral genome?

(A) Double-stranded DNA
(B) Single-stranded DNA
(C) Double-stranded RNA
(D) Single-stranded RNA

Option A) Double-stranded DNA

Explanation:

Note that the presence of thymine, a pyrimidine nitrogenous base in the genome indicates the presence of DNA.

Then, the summation of 28% adenine + 20% thymine + 35% cytosine + 17% guanine to yield 100% confirms that the DNA is double-stranded.

Thus, the structure of the viral genome is Double-stranded DNA.