Nucleic Acids - Mock Test 57

Question 561

The major determinant of the overall rate of denovo purine nucleotide biosynthesis is the concentration of?

A) 5-phosphoribosyl 1-pyrophosphate B) 5-phospho β-D-ribosylamine C) Glycinamide ribosyl-5-phosphate D) Formylglycinamide ribosyl-5-phosphate

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Question 562

Phosphorylation of adenosine to AMP is catalysed by?

A) Adenosine kinase B) Deoxycytidine kinase C) Adenylosuccinase D) Adenylosuccinate synthetase

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Question 563

Conversion of inosine monophosphate to xanthine monophosphate is catalysed by?

A) IMP dehydrogenase B) Formyl transferase C) Xanthine-guanine phosphoribosyl transferase D) Adenine phosphoribosyl transferase

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Question 564

The cofactors required for synthesis of adenylosuccinate are?

A) ATP, Mg++ B) ADP C) GTP, Mg++ D) GDP

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Question 565

Ring closure of formimidoimidazole carboxamide ribosyl-5-phosphate yields the first purine nucleotide?

A) AMP B) IMP C) XMP D) GMP

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Question 566

In purine biosynthesis ring closure in the molecule formyl glycinamide ribosyl-5- phosphate requires the cofactors?

A) ADP B) NAD C) FAD D) ATP and Mg++

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Question 567

In purine nucleus nitrogen atom at 1 position is derived from?

A) Aspartate B) Glutamate C) Glycine D) Alanine

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Question 568

In purine biosynthesis carbon atoms at 4 and 5 position and N at 7 position are contributed by?

A) Glycine B) Glutamine C) Alanine D) Threonine

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Question 569

Intestinal nucleosidases act on nucleosides and produce?

A) Purine base only B) Phosphate only C) Sugar only D) Purine or pyrimidine bases and sugars

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Question 570

The degradation of RNA by pancreatic ribonuclease produces?

A) Nucleoside 2-Phosphates B) Nucleoside 5′-phosphates C) Oligonucleosides D) Nucleoside 3′-phosphate and oligonucleotide

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