12 Questions
What is the primary purpose of the coordinated feedback mechanisms in the biosynthesis of purine and pyrimidine ribonucleotide triphosphates (NTPs) and dNTPs?
To ensure their production in appropriate quantities and at times that match varying physiologic demand, such as cell division.
What is the initial step in the de novo synthesis of purine nucleotides?
The transfer of pyrophosphate group from ATP to ribose-5-phosphate by the enzyme PRPP synthetase.
According to the passage, what is the fate of dietary purines and pyrimidines when consumed by humans?
They are not incorporated directly into tissue, even when the diet is rich in nucleoproteins.
How is the purine ring assembled in the de novo synthesis of purine nucleotides?
The purine ring is assembled piece by piece with all the intermediates attached to ribose-5-phosphate.
What is the role of PRPP (Phospho Ribosyl Pyro Phosphate) in the de novo synthesis of purine nucleotides?
PRPP is formed from ribose-5-phosphate by the transfer of pyrophosphate group from ATP by the enzyme PRPP synthetase.
Which compounds inhibit the formation of tetrahydrofolates and block purine synthesis?
Azaserine, diazanorleucine, and mercaptopurine
What is the fate of injected purine or pyrimidine analogs, including potential anticancer drugs, according to the passage?
They are utilized as substrates for the biosynthesis of purine and pyrimidine ribonucleotide triphosphates (NTPs) and dNTPs.
Which enzymes catalyze the formation of adenylate and guanylate in the purine salvage pathway?
Adenine phosphoribosyltransferase and hypoxanthine-guanine phosphoribosyltransferase
From where do the nitrogen and carbon atoms of atoms 4, 5, and 7 of the purine ring derive?
Glycine
Which pathway is known for saving energy by recycling purine bases?
Purine Salvage pathway
Which compounds inhibit the Purine Salvage pathway?
Azaserine, diazanorleucine, and mercaptopurine
What do free purine bases attach to in order to form purine nucleoside monophosphates?
PRPP
Test your knowledge on purine synthesis, inhibition, and salvage pathways. Learn about the sources of nitrogen and carbon atoms in the purine ring and the compounds used in cancer chemotherapy to block purine synthesis.
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