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
Last Answer : Answer : A
Description : Increased urinary excretion of orotic acid can occur in deficiency of (A) Orotate phosphoribosyl transferase (B) OMP decarboxylase (C) Mitochondrial ornithine transcarbamoylase (D) Any of the above
Last Answer : Answer : D
Description : Methotrexate blocks the synthesis of thymidine monophosphate by inhibiting the activity of the enzyme: (A) Dihydrofolate reductase (B) Orotate phosphoribosyl transferase (C) Ribonucleotide reductase (D) Dihydroorotase
Description : An enzyme of pyrimidine nucleotide biosynthesis sensitive to allosteric regulation is (A) Aspartate transcarbamoylase (B) Dihydroorotase (C) Dihydroorotate dehydrogenase (D) Orotidylic acid decarboxylase
Description : Enzymic deficiency in β-aminoisobutyric aciduria is (A) Adenosine deaminase (B) Xanthine oxidase (C) Orotidylate decarboxylase (D) Transaminase
Description : A cofactor in the conversion of dihydroorotate to orotic acid, catalysed by the enzyme dihydroorotate dehydrogenase is (A) FAD (B) FMN (C) NAD (D) NADP
Last Answer : Answer : C
Description : An alternate substrate for orotate phosphoribosyl transferase is (A) Allopurinol (B) Xanthine (C) Hypoxanthine (D) Adenine
Description : An inborn error, maple syrup urine disease is due to deficiency of the enzyme: (A) Isovaleryl-CoAhydrogenase (B) Phenylalnine hydroxylase (C) Adenosyl transferase (D) α-Ketoacid decarboxylase
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 : Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of (A) Carbamoyl aspartate (B) Orotate (C) Carbamoyl phosphate (D) Dihydroorotate
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
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
Last Answer : Answer : B
Description : All of the following occur in orotic aciduria except (A) Increased synthesis of pyrimidine nucleotides (B) Increased excretion of orotic acid in urine (C) Decreased synthesis of cytidine triphosphate (D) Retardation of growth
Description : Orotic aciduria can be controlled by (A) Oral administration of orotic acid (B) Decreasing the dietary intake of orotic acid (C) Decreasing the dietary intake of pyrimidines (D) Oral administration of uridine
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 : Lesch-Nyhan syndrome, the sex linked recessive disorder is due to the lack of the enzyme: (A) Hypoxanthine-guanine phosphoribosyl transferse (B) Xanthine oxidase (C) Adenine phosphoribosyl transferase (D) Adenosine deaminase
Description : In the synthetic pathway of epinephrine, disulfiram (antabuse) inhibits the enzyme: (A) Tyrosine hydroxylase (B) Dopamine β-hydroxylase (C) DOPA decarboxylase (D) N-methyl transferase
Description : Which of the following is a disease modifying antirheumatic drug whose active metabolite inhibits the enzyme dihydro-orotate dehydrogenase: A. Leflunomide B. Nimesulide C. Sulfasalazine D. Colchicine
Last Answer : A. Leflunomide
Description : The enzyme catalyzing conversion of androstenedione to testosterone is a (A) Oxygenase (B) Dehydrogenase (C) Isomerase (D) Decarboxylase
Description : The rate limiting enzyme in the synthesis of catecholamines is: A. Tyrosine hydroxylase B. Dopa decarboxylase C. Dopamine β-hydroxylase D. Noradrenaline N-methyl transferase
Last Answer : A. Tyrosine hydroxylase
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 : 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 : 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
Description : Which of the following enzyme defects is associated with a characteristic body odour? 1) Phenylalanine aminotransferase 2) Galactose0-phosphate-uridyltransferase 3) Ornithine transcarbamylase deficiency 4) Fumaryl acetoacetase 5) Branched chain ketoacid decarboxylase
Last Answer : Answers-5 The following inborn errors of amino acid metabolism are associated with abnormal odours: Glutaric acidaemia type II (sweaty feet), hawkinsinuria (swimming pool), isovaleric acidaemia (sweaty feet), ... The general rule is that if a child smells peculiar he requires a metabolic work-up.
Description : The rate limiting step in catecholamine synthesis is catalysed by (A) Phenylalanine hydroxylase (B) Tyrosine hydroxylase (C) Dopa decarboxylase (D) Phenylethanolamine N-methyl transferase
Description : The biosynthesis of both Catecholamine and serotonin require (A) Tyrosine hydroxylase (B) N-methyl transferase (C) Aromatic amino acid decarboxylase (D) Tryptophan pyrrolase
Description : A deficiency of copper effects the formation of normal collagen by reducing the activity of which of the following enzyme? (A) Prolyl hydroxylase (B) Lysyl oxidase (C) Lysyl hydroxylase (D) Glucosyl transferase
Description : The decarboxylation reaction in HMP shunt is catalysed by (A) Gluconolactone hydrolase (B) 6-Phosphogluconate dehydrogenase (C) 6-Phosphogluconate decarboxylase (D) Transaldolase
Description : Methyl malonic aciduria is seen in a deficiency of (A) Vitamin B6 (B) Folic acid (C) Thiamine (D) Vitamin B12
Description : Methyl malonic aciduria is seen in the deficiency of (A) Vitamin B6 (B) Folic acid (C) Thiamine (D) Vitamin B12
Description : Neonatal tyrosinemia is due to deficiency of the enzyme: (A) p-Hydroxyphenylpyruvate hydroxylase (B) Fumarylacetoacetate hydrolase (C) Phenylalanine hydroxylase (D) Tyrosine dehydrogenase
Description : Albinism is due to deficiency of the enzyme: (A) Phenylalanine hydroxylase (B) Tyrosinase (C) p-Hydroxyphenylpyruvic acid oxidase (D) Tyrosine dehydrogenase
Description : Acute hemolytic episode after administration of antimalarial, primaquin, is due to deficiency of the enzyme: (A) 6-Phosphogluconate dehydrogenase (B) Glucose-6-phosphate dehydrogenase (C) Epimerase (D) Transketolase
Description : Acute hemolytic anemia in person’s sensitive to the Fava beans is due to the deficiency of the enzyme: (A) Pyruvate dehydrogenase (B) G-6-PD (C) Aconitase (D) Transketolase
Description : Hemolytic anemia is caused by the deficiency of certain enzymes of the pentose phosphate pathway, the principal enzyme involved is (A) Glucose-6-phosphate dehydrogenase (B) Aldolase (C) Fructose 1, 6-bisphosphatase (D) Phosphohexose isomerase
Description : Dietary deficiency of thiamin inhibits the activity of the enzyme: (A) Pyruvate kinase (B) Pyruvate dehydrogenase (C) Phosphofructokinase (D) Enolase
Description : Which one of the following statements concerning glucose-6-phosphate dehydrogenase deficiency is correct? (A) Young R.B.Cs, particularly reticulocytes, contain the highest enzyme activity cells show less enzyme ... PD gene (D) G-6-PD deficiency is precipitated by ingestion of drugs such as aspirin
Description : The “Primaquin sensitivity types of haemolytic anaemia has been found to relate to reduced R.B.C activity of which enzyme? (A) Pyruvate kinase deficiency (B) Glucose-6-phosphatase deficiency (C) Glucose-6-p dehydrogenase deficiency (D) Hexokinase deficiency
Last Answer : C
Description : Absence of the enzyme argininosuccinate synthetase causes (A) Argininosuccinic aciduria (B) Hyperargininemia (C) Tricorrhexis nodosa (D) Citrullinemia
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 : All of the following enzymes are unique to purine nucleotide synthesis except (A) PRPP synthetase (B) PRPP glutamyl amido transferase (C) Adenylosuccinate synthetase (D) IMP dehydrogenase
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
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 : Conversion of pyruvate into acetyl CoA is catalysed by (A) Pyruvate dehydrogenase (B) Didrolipoyl acetyl transferase (C) Dihydrolipoyl dehydrogenase (D) All the 3 acting in concert
Description : Acetyl-CoA is the principal building block of fatty acids. It is produced within the mitochondria and does not diffuse readily into cytosol. The availability of acetyl CoA involves (A) Carnitine acyl transferase (B) Pyruvate dehydrogenase (C) Citrate lyase (D) Thiolase
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 : Acute intermittent porphyria (paraoxymal porphyria) is caused due to deficiency of (A) Uroporphyrinogen I synthase (B) ALA synthase (C) Coproporphyrinogen oxidase (D) Uroporphyrinogen decarboxylase