Q: About Nucleotide Metabolism

Question NcM-01


Gout is characterized by elevated uric acid concentrations in blood and urine due to a variety of metabolic abnormalities that lead to the overproduction of purine nucleotides. Allopurinol is used in the treatment of gout because this drug, and its metabolic product, alloxanthine, act as inhibitors of:


a)       Xanthine Oxidase

b)      PRPP synthetase

c)       Adenyl succinate synthase

d)      Hypoxhantine guanine phosphoribosyl transferase

 e)       Nucleotides


     Answer to NcM-01



Question NcM-02


Both the salvage and de novo synthesis pathways of purine and pyrimidine biosynthesis lead to the production of nucleoside-5′-phosphates through the utilization of an activated sugar.

The activated sugar intermediate used for this purpose is:


a)     Glucose 6 (P)

b)     Ribose 5 (P)

c)      5 Phosphoribosyl 1 pyrophosphate

d)     Ribosyl pyrophosphate

e)     Deoxyribosyl 5 pirophosphate



Question NcM-03


The first purine nucleotide that is fully formed in metabolism is:


a)     IMP

b)     AMP

c)      GMP

d)     XMP

e)     ADP

f)       ATP

g)     GTP



Question NcM-04


Three amino acids that donate amine groups for the purine biosynthesis are


a)     Glycine, glutamine, aspartate

b)     Glycine, beta-alanine, aspartate

c)      Glycine, alanine, aspartate

d)     Lysine, glutamine, aspartate

e)     Lysine, glutamate, asparagine

f)       Lysine, glycine, asparagine



Question NcM-05


Hereditary Orotic aciduria is characterized by severe anemia, growth retardation, and high levels of orotic acid excretion. It is produced by deficit of enzymes related with:


a)     synthesis of pyrimidine nucleotides

b)     catabolism of pyrimidine nucleotides

c)      synthesis of purine nucleotides

d)     catabolism of purine nucleotides

e)     synthesis of Hem

f)       catabolism of Hem