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
Last Answer : Answer : C
Description : The key substance in the synthesis of purine, phosphoribosyl pyrophosphate is formed by (A) α-D-ribose 5-phosphate (B) 5-phospho β-D-ribosylamine (C) D-ribose (D) Deoxyribose
Last Answer : Answer : A
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 : 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 : 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 : 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 : An alternate substrate for orotate phosphoribosyl transferase is (A) Allopurinol (B) Xanthine (C) Hypoxanthine (D) Adenine
Last Answer : Answer : D
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 : 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 : 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 : An autosomal recessive disorder, xanthinuria is due to deficiency of the enzymes: (A) Adenosine deaminase (B) Xanthine oxidase (C) HGPRTase (D) Transaminase
Description : 5-Phosphoribosyl-1-pyrophosphate is required for the synthesis of (A) Purine nucleotides (B) Pyrimidine nucleotides (C) Both (A) and (B) (D) None of these
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 allosteric inhibitor of PRPP glutamyl amido transferase is (A) AMP (B) ADP (C) GMP (D) All of these
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 : 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 : 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 : Uracil and ribose form (A) Uridine (B) Cytidine (C) Guanosine (D) Adenosine
Description : Of Which warburg’s yellow enzyme contains as a prosthetic group? (A) Thiamine pyrophosphate (B) Biotin (C) NAD+ (D) Riboflavin-5-phosphate
Description : The substrate for amylase is (A) Cane sugar (B) Starch (C) Lactose (D) Ribose
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 : A coenzyme present in phosphorylase is (A) NAD (B) Pyridoxal phosphate (C) Thiamin pyrophosphate (D) Coenzyme A
Description : Cocarboxylase is (A) Thiamine pyrophosphate (B) Pyridoxal phosphate (C) Biotin (D) CoA
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 : A key substance in the committed step of pyrimidines biosynthesis is (A) Ribose-5-phosphate (B) Carbamoyl phosphate (C) ATP (D) Glutamine
Description : The first pentose formed in HMP shunt is (A) Ribose-5-phosphate (B) Ribulose-5-phosphate (C) Xylose-5-phosphate (D)Xylulose-5-phosphate
Description : Glucose-6-phosphate dehydrogenase is induced by (A) 6-Phosphogluconolactone (B) Glucose-6-phosphate (C) Ribose-5-phosphate (D) Insulin
Description : Pentosuria is a rare hereditary disease is characterized by increased urinary excretion of (A) L-xylulose (B) Xylitol (C) Xylulose 5-phosphate (D) Ribose 5-phosphate
Description : Xylulose-5-phosphate serves as a donar of active glycolaldehyde, the acceptor is (A) Erythrose 4-phosphate (B) Ribose 5-phosphate (C) Glyceraldehyde 3-phosphate (D) Sedoheptulose 7-phosphate
Description : In pentose phosphate pathway, D-ribulose5-phosphate is converted to D-ribose-5- phosphate by the enzyme: (A) Fumarase (B) Ketoisomerase (C) G-6-PD (D) Epimerase
Description : In RNA, apart from ribose and phosphate, all following are present except (A) Adenine (B) Guanine (C) Thymine (D) Cytosine
Description : Lesch-Nyhan syndrome, the sex linked, recessive absence of HGPRTase, may lead to (A) Compulsive self destructive behaviour with elevated levels of urate in serum (B) Hypouricemia due to liver damage (C) Failure to thrive and megaloblastic anemia (D) Protein intolerance and hepatic encephalopathy
Description : A substrate for the enzyme aldolase is (A) galactose-6-phosphate (B) isocitric acid (C) Glucose-1-phosphate (D) Fructose 1, 6 diphosphate
Description : Which of the following enzymes incorporates inorganic phosphate into the substrate? (A) Phosphoglycerate kinase (B) Glyceraldehyde-3-phosphate dehydrogenase (C) Pyruvate kinase (D) Enolase
Description : The example of generation of a high energy phosphate at the substrate level in the citric acid cycle is the reaction: (A) Isocitrate α-Ketoglutarate (B) Succinate α-fumarate (C) Malate α-oxaloacetate (D) Succinyl CoA α-Succinate
Description : The reaction catalysed by phosphofructokinase (A) Is activated by high concentrations of ATP and citrate (B) Uses fruitose-1-phosphate as substrate (C) Is the rate-limiting reaction of the glycolytic pathway (D) Is inhibited by fructose 2, 6-bisphosphate
Last Answer : C
Description : Two examples of substrate level phosphorylation in EM pathway of glucose metabolism are in the reactions of (A) 1,3 bisphosphoglycerate and phosphoenol pyruvate (B) Glucose-6 phosphate ... phosphate (C) 3 phosphoglyceraldehyde and phosphoenolpyruvate (D) 1,3 diphosphoglycerate and 2-phosphoglycerate
Last Answer : A
Description : Pyrimidine and purine nucleoside biosynthesis share a common precursor: (A) PRPP (B) Glycine (C) Fumarate (D) Alanine
Description : The 5- carbon compounds produced during dark reaction of photosynthesis is (A) Ribose phosphate (B) Xylulose phosphate (C) Ribulose bis phosphate (D) Seda heptulose phosphate
Last Answer : (C) Ribulose bis phosphate
Description : Which one of the following is a non - reducing carbohydrate? (a) Maltose (b) Sucrose (c) Lactose (d) Ribose 5-phosphate
Last Answer : (b) Sucrose
Description : Polynucleotide chain of DNA contains (a) a nitrogenous base, deoxyribose sugar and phosphate group (b) a nitrogenous base, ribose sugar and phosphate group (c) deoxyribose sugar ribose sugar and phosphate group (d) a nitrogenous base and phosphate group only
Last Answer : Ans:(a)
Description : Which one of the following statements is not true of RNA? a. RNA contains the monosaccharide ribose. b. RNA is primarily a single-stranded molecule. c. RNA has a sugar-phosphate backbone. d. RNA contains five different nucleotides.
Last Answer : d. RNA contains five different nucleotides.
Description : A molecule of ATP contains a. Ribose But No Adenine. b. Phosphate But No Ribose. c. Adenine But No Deoxyribose. d. Deoxyribose But No Thymine.
Last Answer : b. Phosphate But No Ribose.
Description : Which one of the following is NOT part of an ATP MOLECULE? a. Phosphate group b. Cofactor c. Ribose d. Adenine
Last Answer : b. Cofactor
Description : Write a note on ATP (Adenosine Tri-Phosphate). -Biology
Last Answer : answer:
Description : Which one of the following biomolecules is correctly characterized? (a) Lecithin-a phosphorylated glyceride found in cell membrane. (b) Palmitic acid - an unsaturated fatty acid with 18 carbon atoms. ... Alanine amino acid - contains an amino group and an acidic group anywhere in the molecule.
Last Answer : (a) Lecithin-a phosphorylated glyceride found in cell membrane
Description : Which of the following is known as bone forming enzyme? (A) Alkaline phosphatase (B) Acid phosphatase (C) Leucine aminopeptidase (D) γ-glutamyl transpeptidase
Description : Serum gamma glutamyl transpeptidase is raised in (A) Haemolytic jaundice (B) Myocardial infarction (C) Alcoholic hepatitis (D) Acute cholecystitis