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
Last Answer : Answer : B
Description : An enzyme common to de novo synthesis of pyrimidine nucleotides and urea is (A) Urease (B) Carbamoyl phosphate synthetase (C) Aspartate transcarbamoylase (D) Argininosuccinase
Description : Transfer of the carbamoyl moiety of carbamoyl phosphate to ornithine is catalysed by a liver mitochondrial enzyme: (A) Carbamoyl phosphate synthetase (B) Ornithine transcarbamoylase (C) N-acetyl glutamate synthetase (D) N-acetyl glutamate hydrolase
Description : The following enzyme of urea cycle is present in cytosol: (A) Argininosuccinic acid synthetase (B) Argininosuccinase (C) Arginase (D) All of these
Last Answer : Answer : D
Description : Hyperammonaemia type I results from congenital absence of (A) Glutamate dehydrogenase (B) Carbamoyl phosphate synthetase (C) Ornithine transcarbamoylase (D) None of these
Description : De novo synthesis of pyrimidine nucleotides is regulated by (A) Carbamoyl phosphate synthetase (B) Aspartate transcarbamoylase (C) Both (A) and (B) (D) None of these
Last Answer : Answer : C
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 : The metabolite which sustains urea cycle is (A) Ornithine (B) Citrulline (C) Carbamoyl phosphate (D) n-acetyl glutamate
Description : Enzyme deficient in Hyperammonemia type II is (A) Glutamine synthetase (B) Glutaminase (C) Ornithine transcarbamoylase (D) Carbamoylphosphate synthetase
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 : 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
Last Answer : Answer : A
Description : The enzyme carbamoyl phosphate synthetase requires (A) Mg++ (B) Ca++ (C) Na+ (D) K+
Description : In ornithine cycle, enzyme arginase breaks down arginine into
Last Answer : In ornithine cycle, enzyme arginase breaks down arginine into A. Citrulline and ammonia B. Ornithine ... C. Ornithine and urea D. Citruline and urea
Description : An enzyme which is excreted in urine is (A) Lactase dehydrogenase (B) Amylase (C) Ornithine transcarbamoylase (D) None of these
Description : ATP is required in following reactions of urea cycle: (A) Synthesis of carbamoyl phosphate and citrulline (B) Synthesis of citrulline and argininosuccinate (C) Synthesis of argininosuccinate and arginine (D) Synthesis of carbamoyl phosphate and argininosuccinate
Description : Enzyme involved in joining together two substrates is (A) Glutamine synthetase (B) Aldolase (C) Gunaine deaminase (D) Arginase
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 : 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 : An important finding in Hyperammonemia type II is (A) Increased serum gluatmine level (B) Enlarged liver (C) Mental retardation (D) Increased carbamoyl phosphate synthetase level
Description : Carbamoyl phosphate synthetase structure is marked by change in the presence of (A) N-Acetyl glutamate (B) N-Acetyl Aspartate (C) Neuraminic acid (D) Oxalate
Description : Urea is produced physiologically by the action of the enzyme: (A) Urease (B) Glutaminase (C) Arginase (D) None of these
Description : Carbamoyl phosphate required for urea synthesis is formed in (A) Cytosol (B) Mitochondria (C) Both (A) and (B) (D) None of these
Description : Congenital deficiency of ornithine transcarbamoylase causes (A) Hyperammonaemia type I (B) Hyperammonaemia type II (C) Hyperornithinaemia (D) Citrullinaemia
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
Description : In urea synthesis, the amino acid functioning solely as an enzyme activator: (A) N-acetyl glutamate(B) Ornithine (C) Citrulline (D) Arginine
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 following 4 amino acids are required for completion of urea cycle except (A) Aspartic acid (B) Arginine (C) Ornithine (D) Glycine
Description : An amino acid not involved in urea cycle is (A) Arginine (B) Histidine (C) Ornithine (D) Citrulline
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
Description : The enzyme that converts glucose to glucose-6-phosphate is (A) Phosphatase (B) Hexokinase (C) Phosphorylase (D) Glucose synthetase
Description : The ornithine cycle removes two waste products from the blood in liver. These products are (a) CO2 and ammonia (b) ammonia and uric acid (c) CO2 and urea (d) ammonia and urea.
Last Answer : a) CO2 and ammonia
Description : In ureotelic animals, urea is formed by (a) Krebs’ cycle (b) EM pathway (c) Ornithine cycle (d) Cori cycle.
Last Answer : (c) Ornithine cycle
Description : Conversion of ammonia to urea is done by (a) ornithine cycle (b) arginine cycle (c) fumaric cycle (d) citrulline cycle.
Last Answer : (a) ornithine cycle
Description : In ornithine cycle, which of the following wastes are removed from the blood? (a) CO2 and urea (b) Ammonia and urea (c) CO2 and ammonia (d) Urea and urine
Last Answer : (c) CO2 and ammonia
Description : An enzyme of the citric acid cycle also found outside the mitochondria is (A) Isocitrate dehydrogenase (B) Citrate synthetase (C) α-Ketoglutarate dehydrogenase (D) Malate dehydrogenase
Description : A key substance in the committed step of pyrimidines biosynthesis is (A) Ribose-5-phosphate (B) Carbamoyl phosphate (C) ATP (D) Glutamine
Description : The two nitrogen of the pyrimidine ring are contributed by (A) Ammonia and glycine (B) Asparate and carbamoyl phosphate (C) Glutamine and ammonia (D) Aspartate and ammonia
Description : Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of (A) Carbamoyl aspartate (B) Orotate (C) Carbamoyl phosphate (D) Dihydroorotate
Description : The highest energy level is present amongst the following in (A) 1, 3-Biphosphoglycerate (B) Creatine phosphate (C) Carbamoyl phosphate (D) Phosphoenol pyruvate
Description : Which of the following contributes nitrogen atoms to both purine and pyrimidine rings? (A) Aspartate (B) Carbamoyl phosphate (C) CO2 (D) Glutamine
Description : The enzyme aspartate transcarbamoylase of pyrimidine biosynthesis is inhibited by (A) ATP (B) ADP (C) AMP (D) CTP
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 : Synthesis of polyunsaturated fatty acids involves the enzyme systems: (A) Acyl transferase and hydratase (B) Desaturase and elongase (C) Ketoacyl-CoA reductase and hydratase (D) Dihydroxyacetone phosphate
Description : Arginase enzyme is formed by (a) Spleen (b) Liver (c) Kidney (d) All
Last Answer : (b) Liver
Description : Enzyme arginase is found in (a) Mouth cavity (b) Stomach (c) Intestine (d) Liver
Last Answer : (d) Liver
Description : CTP synthetase forms CTP from (A) CDP and inorganic phosphate (B) CDP and ATP (C) UTP and glutamine (D) UTP and glutamate
Description : Pyridoxal phosphate is a coenzyme for (A) Glycogen synthetase (B) Phosphorylase (C) Both (A) and (B) (D) None of these
Description : All the following statements about charging of tRNA are correct except (A) It is catalysed by amino acyl tRNA synthetase (B) ATP is converted into ADP and Pi in this reaction (C) The enzyme recognizes the tRNA and the amino acid (D) There is a separate enzyme for each tRNA
Description : The enzyme amino acyl tRNA synthetase is involved in (A) Dissociation of discharged tRNA from 80S ribosome (B) Charging of tRNA with specific amino acids (C) Termination of protein synthesis (D) Nucleophilic attack on esterified carboxyl group of peptidyl tRNA