Metabolic pathway of nucleotides. Catabolism and anabolism

1. End product of purine catabolism is…

A. urea,

B. indole;

C. uric acid;

D. indican;

E. creatinine.

2. End product of pyrimidine catabolism is…

A. urea,

B. indole;

C. uric acid;

D. indican;

E. creatinine.

3. Patient in Lesh- Nyhan syndrome has defect in enzyme of…

A. purine degradation;

B. pyrimidine catabolism;

C. purine de novo synthesis;

D. pyrimidine de novo synthesis;

E. purine salvage.

4. Allopurinol administrated in gout is analog of…

A. uric acid;

B. xanthine;

C. guanine;

D. hypoxanthine;

E. inosine.

5. The common precursor for AMP and GMP is….

A.xanthine;

B. orotic acid;

C. xanthosine monophosphate;

D. inosine monophosphate;

E. adenylosuccinate.

6. The common precursor for pyrimidine nucleotides is….

A.xanthine;

B. orotic acid;

C. xanthosine monophosphate;

D. inosine monophosphate;

E. adenylosuccinate.

7. As sources of the nitrogen and carbon atoms of the purine ring….. are used.

A. aspartate and glycine;

B. glutamine;

C. respiratory CO₂;

D. derivatives from folic acid;

E. all answers are correct.

8. Reduction of ribonucleoside diphosphate to 2’-deoxyribonucleoside diphosphate is catalyzed by…..

A. phosphoribosyl pyrophosphate synthase;

B. carbamoyl phosphate synthase I;

C. carbamoyl phosphate synthase II;

D. xanthine oxidase;

E. ribonucleotide reductase complex.

9. Common mechanism regulation of enzymes participating in biosynthesis of purine and pyrimidine nucleotides is…

A. isosteric regulation;

B. partial proteolysis;

C. dissociation of promoters;

D. feedback regulation;

E. all answers are correct.

10. Common precursor for purine biosynthesis and pyrimidine biosynthesis is…

A. orotic acid;

B. inosine monophosphate;

C. 5-phosphorybosyl 5-pyrophosphate;

D. xanthine;

E. adenylosuccinate.

PRACTICAL LESSON 6