Purine and Pyrimidine Metabolism

Flashcards based on key concepts in purine and pyrimidine metabolism.

What is a nucleoside?

A nucleoside is a base combined with a carbohydrate.

What are nucleotides composed of?

A nucleoside with one or more phosphates.

What two types of sugar are found in nucleic acids?

Ribose in RNA and deoxyribose in DNA.

What is the first purine formed in the purine synthesis pathway?

Inosine 5’ phosphate (IMP).

What is PRPP and its role in nucleotide synthesis?

PRPP stands for 5-phosphoribosyl-1-pyrophosphate, and it is involved in the synthesis of purines, pyrimidines, and other molecules.

What is the key regulatory enzyme in mammalian pyrimidine synthesis?

Carbamoylphosphate synthetase II (CPS II).

What is the end product of purine degradation in some vertebrates?

Uric acid.

What enzyme catalyzes the conversion of ribonucleotides to deoxyribonucleotides?

Ribonucleotide reductase (RR).

How many ATP equivalents are required to synthesize one GTP de novo?

11 ATP equivalents are required.

What is the primary way pyrimidine nucleotides are salvaged?

By adding the nitrogenous base to PRPP.