Which of the pathways for nucleotide biosynthesis builds the base ring on a prpp molecule?
a) purine b) pyrimidine c) both purine and pyrimidine

A) purine

Explanation:

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

Purines are synthesized directly on ribose sugar, in segments.

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

5-Phosphoribosyl-1-pyrophosphate (PRPP). is used for the synthesis of purine (ribose 5-phosphate reacts with ATP to form  ribonucleotide).

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