Question

The base composition of a double-stranded DNA molecule is 26% adenine. What percentage of this molecule is the base guanine? Give only the answer in numerical form so that Moodle will grade your answer correctly. Do not write "%".

Answer 1

Answer:

26

Explanation:

According to Chargaff's rule, a typical DNA molecule must have an equal ratio of both purine and pyrimidine bases. Purine is made up of Adenine and Guanine bases while pyrimidine is made up of Thymine and Cytosine bases.

Hence, if the amount of Adenine in DNA is 26%, the amount of Guanine would also be 26%. This would leave the remaining 48% of the DNA as Thymine and Cytosine to be shared in an equal proportion of 24% each.

In summary:

If Adenine = 26, Guanine would also be = 26

Adenine + Guanine = 52%

Thymine + Cytosine = 48%