Answer:
A) purine
Explanation:
There are two ways for the synthesis of purines and pyrimidines:
- de novo synthesis-from basic simple units
- "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.
5-Phosphoribosyl-1-pyrophosphate (PRPP). is used for the synthesis of purine (ribose 5-phosphate reacts with ATP to form ribonucleotide).
