Question

What is an important difference between the biosynthesis of purine nucleotides and that of pyrimidine nucleotides?

Answer 1

They include the nucleobases adenine (2) and guanine (3). In DNA, these bases form hydrogen bonds with their complementary pyrimidines, thymine and cytosine, respectively. This is called complementary base pairing. In RNA, the complement of adenine is uracil instead of thymine.