Description : In the pathway of de novo synthesis of purine nucleotides, all the following are allosteric enzymes except (A) PRPP glutamyl amido transferase (B) Adenylosuccinate synthetase (C) IMP dehydrogenase (D) Adenylosuccinase
Last Answer : Answer : D
Description : The first reaction unique to purine nucleotide synthesis is catalysed by (A) PRPP synthetase (B) PRPP glutamyl amido transferase (C) Phosphoribosyl glycinamide synthetase (D) Formyl transferase
Last Answer : Answer : B
Description : GMP is an allosteric inhibitor of all the following except (A) PRPP synthetase (B) PRPP glutamyl amido synthetase (C) IMP dehydrogenase (D) Adenylosuccinate synthetase
Description : An enzyme which acts as allosteric regulator and sensitive to both phosphate concentration and to the purine nucleotides is (A) PRPP synthetase (B) PRPP glutamyl midotransferase (C) HGPR Tase (D) Formyl transferase
Last Answer : Answer : A
Description : In the biosynthesis of purine nucleotides the AMP feed back regulates (A) Adenylosuccinase (B) Adenylosuccinate synthetase (C) IMP dehydrogenase (D) HGPR Tase
Description : PRPP glutamyl amidotransferase, the first enzyme uniquely committed to purine synthesis is feed back inhibited by (A) AMP (B) IMP (C) XMP (D) CMP
Description : An allosteric inhibitor of PRPP glutamyl amido transferase is (A) AMP (B) ADP (C) GMP (D) All of these
Last Answer : Answer : C
Description : All the following statements about primary gout are true except (A) Its inheritance is X-linked recessive (B) It can be due to increased activity of PRPP synthetase (C) It can be ... activity of hypoxanthine guanine phosphoribosyl transferase (D) De novo synthesis of purines is increased in it
Description : All the enzymes required for de novo synthesis of pyrimidine nucleotides are cytosolic except (A) Carbamoyl phosphate synthetase (B) Aspartate transcarbamoylase (C) Dihydro-orotase (D) Dihydro-orotate dehydrogenase
Description : Orotic aciduria type I reflects the deficiency of enzymes: (A) Orotate phosphoribosyl transferase and orotidylate decarboxylase (B) Dihydroorotate dehydrogenase (C) Dihydroorotase (D) Carbamoyl phosphate synthetase
Description : Salvage of purine bases is regulated by (A) Adenosine phosphoribosyl transferase (B) Hypoxanthine guanine phosphoribosyl transferase (C) Availability of PRPP (D) None of these
Description : Ring closure of formimidoimidazole carboxamide ribosyl-5-phosphate yields the first purine nucleotide: (A) AMP (B) IMP (C) XMP (D) GMP
Description : 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
Description : All of the following are allosteric enzymes except (A) Citrate synthetase (B) a-Ketoglutarate dehdrogenase (C) Succinate thiokinase (D) Succinate dehydrogenase
Description : The available PRPP is used preferentially for (A) De novo synthesis of purine nucleotides (B) De novo synthesis of pyrimidine nucleotides (C) Salvage of purine bases (D) Salvage of pyrimidine bases
Description : A common substrate of HGPRTase, APRTase and PRPP glutamyl amidotransferase is (A) Ribose 5 phosphate (B) Phosphoribosyl pyrophosphate (C) Hypoxanthine (D) Adenosine
Description : In inherited deficiency of hypoxanthine guanine phosphoribosyl transferase (A) De novo synthesis of purine nucleotides is decreased (B) Salvage of purines is decreased (C) Salvage of purines is increased (D) Synthesis of uric acid is decreased
Description : De novo synthesis of purine nucleotide occurs in (A) Mitochondria (B) Cytosol (C) Microsmes (D) Ribosomes
Description : An allosteric inhibitor of adenylosuccinate synthetase is (A) AMP (B) ADP (C) GMP (D) GDP
Description : Phosphorylation of adenosine to AMP is catalysed by (A) Adenosine kinase (B) Deoxycytidine kinase (C) Adenylosuccinase (D) Adenylosuccinate synthetase
Description : Thiamine is essential for (A) Pyruvate dehydrogenase (B) Isocitrate dehydrogenase (C) Succinate dehydrogenase (D) Acetyl CoA synthetase ENZYMES 165
Description : A flavoprotein in pyruvate dehydrogenase complex is (A) Pyruvate dehydrogenase (B) Didrolipoyl acetyl transferase (C) Dihydrolipoyl dehydrogenase (D) None of these ENZYMES 161
Description : Formation of acetyl CoA from pyruvate for de novo synthesis of fatty acids requires (A) Pyruvate dehydrogenase complex (B) Citrate synthetase (C) ATP citrate lyase (D) All of these
Description : Acetyl CoA required for extra mitochondrial fatty acid synthesis is produced by (A) Pyruvate dehydrogenase complex (B) Citrate lyase (C) Thiolase (D) Carnitine-acyl transferase
Description : Estimation of gamma glutamyl transferase is useful to detect which condition?
Last Answer : Alcohol abuse.
Description : The following abnormality in PRPP synthetase can cause primary gout: (A) High Vmax (B) Low Km (C) Resistance to allosteric inihbition. (D) All of these
Description : Cytosolic carbamoyl phosphate synthetase is activated by (A) Glutamine (B) PRPP (C) ATP (D) Aspartate
Description : Cytosolic carbamoyl phosphate synthetase is inhibited by (A) UTP (B) CTP (C) PRPP (D) TMP
Description : AMP is an allosteric inhibitor of (A) PRPP synthetase (B) Adenylosucciante synthetase (C) Both (A) and (B) (D) None of these
Description : PRPP synthetase is allosterically inhibited by (A) AMP (B) ADP (C) GMP (D) All of these
Description : Pyrimidine and purine nucleoside biosynthesis share a common precursor: (A) PRPP (B) Glycine (C) Fumarate (D) Alanine
Description : 6-Mercapto purine inhibits the conversion of (A) IMP→ XMP (B) Ribose 5 phosphate → PRPP (C) PRPP → 5-phospho →β -D-ribosylamine (D) Glycinamide ribosyl 5-phosphate → formylglycinamide ribosyl-5-phosphate
Description : Hyperargininemia, a defect in urea synthesis develops due to deficiency of the enzyme: (A) Ornithine transcarbamoylase (B) Argininosuccinase (C) Arginase (D) Argininosuccinate synthetase ENZYMES 157
Description : Cytosolic and mitochondrial carbamoyl phosphate synthetase have the following similarity: (A) Both use ammonia as a substance (B) Both provide carbamoyl phosphate for urea synthesis (C) Both require N-acetylglutamate as an activator (D) Both are allosteric enzymes
Description : A pyrimidine nucleotide is (A) GMP (B) AMP (C) CMP (D) IMP
Description : The cofactors required for synthesis of adenylosuccinate are (A) ATP, Mg++ (B) ADP (C) GTP, Mg++ (D) GDP
Description : Myeloma cells are lacking in (A) TMP synthetase (B) Formyl transferase (C) HGPRT (D) All of these
Description : In the biosynthesis of cholesterol, the rate limiting enzyme is (A) Mevalonate kinase (B) HMG-CoA synthetase (C) HMG-CoA reductase (D) Cis-prenyl transferase
Description : The enzyme required for salvage of free purine bases is (A) Adenine phosphoribosyl transferase (B) Hypoxanthine guanine phosphoribosyl transferase (C) Both (A) and (B) (D) None of these
Description : The mechanism of synthesis of DNA and RNA are similar to all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is (D) They require a primer
Description : The mechanism of synthesis of DNA and RNA are similar in all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is 5’ → 3’ (D) They require a primer
Description : Genetic code is (A) Collection of codon (B) Collection of amino acids (C) Collection of purine nucleotide (D) Collection of pyrimidine nucleotide
Description : 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
Description : A purine nucleotide is (A) AMP (B) UMP (C) CMP (D) TMP
Description : A nucleotide consists of (A) A nitrogenous base like choline (B) Purine + pyrimidine base + sugar + phosphorous (C) Purine or pyrimidine base + sugar (D) Purine or pyrimidine base + phosphorous
Description : An allosteric inhibitor of IMP dehydrogenase is (A) AMP (B) ADP (C) GMP (D) GDP
Description : The following enzymes on the left are responsible for the synthesis of the neurotransmitters on the right: a. monoamine oxidase: noradrenaline b. cholinesterase: acetylcholine c. catechol-o-methyl transferase: dopamine d. dopa decarboxylase: adrenaline
Last Answer : dopa decarboxylase: adrenaline
Description : L-glutamic acid is subjected to oxidative deaminition by (A) L-amino acid dehydrogenase (B) L-glutamate dehydrogenase (C) Glutaminase (D) Glutamine synthetase
Description : Hyperammonaemia type I results from congenital absence of (A) Glutamate dehydrogenase (B) Carbamoyl phosphate synthetase (C) Ornithine transcarbamoylase (D) None of these
Description : An enzyme of pyrimidine nucleotides biosynthesis regulated at the genetic level by apparently coordinate repression and derepression is (A) Carbamoyl phosphate synthetase (B) Dihydroorotate dehydrogenase (C) Thymidine kinase (D) Deoxycytidine kinase