Question

One way in which the anabolism of pyrimidine nucleotides differs from that of purine nucleotides is that

a) the pyrimidine ring is assembled before being bonded to the ribose phosphate, whereas the purine ring is bonded to the ribose phosphate as it is formed
b) there is no feedback inhibition in the anabolism of pyrimidine nucleotides, while feedback inhibition is important in the synthesis of purine nucleotides

Answer 1

a) the pyrimidine ring is assembled before being bonded to the ribose phosphate, whereas the purine ring is bonded to the ribose phosphate as it is formed

Step-by-step explanation:

There are two ways for the synthesis of purines and pyrimidines:

1. de novo synthesis-from basic simple units
2. "recycling" synthesis-reuse of metabolites

Purines are synthesized directly on ribose sugar, in segments.

Pyrimidines are attached to the ribose after the synthesis of the base.