Miesfeld Chapter 18

Uric acid is an example of a _________.

• a.nucleotide
• b.ribonucleoside
• c.pyrimidine
• d.purine
• e.tyrosine derivative

Which nucleotide is required to make AMP?

• a.CTP
• b.GTP
• c.TTP
• d.UTP
• e.NTP

IMP is the precursor for which of the following nucleoside monophosphates?

• A.AMP.
• B.GMP.
• C.XMP.
• D.A and B.
• E.All of the above.

Which of the following statements is true regarding regulation of purine nucleotide biosynthesis?

• A.Glutamine-PRPP amidotransferase is inhibited by purine monophosphates.
• B.IMP dehydrogenase is inhibited by AMP.
• C.Adenylosuccinate synthetase is inhibited by ATP.
• D.A and C are correct.
• E.All the above statements are correct.

The N7 in the purine ring is contributed by which of the following molecules?

• A.Aspartate
• B.Glycine
• C.Glutamate
• D.Glutamine
• Arginine

The N3 in the pyrimidine ring is contributed by which of the following molecules?

• A.Aspartate
• B.Glycine
• C.Glutamate
• D.Glutamine
• E.Arginine

Allipuronol is an agent used in the treatment of chronic gout. Which of the following enzymes does it inhibit?

• A.Xanthine oxidase
• B.Ribonucleotide reductase
• C.Adenosine deaminase
• D.Urate oxidase

Which of the following statements is correct for the regulation of aspartate transcarbamoylase (ATCase)?

• A.This enzyme is regulated in both mammals and bacteria.
• B.In bacteria ATCase is activated by PRPP.
• C.In mammals ATCase is activated by ATP.
• D.In bacteria ATCase is allosterically regulated by CTP.
• E.In mammals ATCase is inhibited by UTP.

Which of the following donates the methyl group used in the formation of dTMP from dUMP?

• A.Serine
• B.5,10-Methylenetetrahydrofolate
• C.Folate
• D.Dihydrofolate
• E.Formate