Question

If a DNA molecule is 30% cytosine (C), what is the percentage of guanine (G)?

a) 20%
b) 30%
c) 40%
d) 70%

Answer 1

According to Chargaff's rules, the percentage of guanine in a DNA molecule with 30% cytosine is also 30%.

Step-by-step explanation:

If a DNA molecule is 30% cytosine (C), then according to Chargaff's rules, which states that in DNA, the amount of guanine is equal to the amount of cytosine, and the amount of adenine is equal to the amount of thymine, the percentage of guanine (G) will also be 30%. Therefore, the correct answer to the student's question is b) 30%.