Description : Regulation of haem synthesis occurs by (A) Covalent modification (B) Repression - derepression (C) Induction (D) Allosteric regulation
Last Answer : Answer : B
Description : Acetyl CoA carboxylase regulates fatty acid synthesis by which of the following mechanism? (A) Allosteric regulation (B) Covalent modification (C) Induction and repression (D) All of these
Last Answer : Answer : D
Description : Pyruvate carboxylase is regulated by (A) Induction (B) Repression (C) Allosteric regulation(D) All of these
Last Answer : D
Description : Pyruvate dehydrogenase complex is regulated by (A) Covalent modification (B) Allosteric regulation (C) Both (A) and (B) (D) None of these
Last Answer : Answer : C
Description : In conversion of lactic acid to glucose, three reactions of glycolytic pathway are circumvented, which of the following enzymes do not participate? (A) Pyruvate carboxylase (B) Phosphoenol pyruvate carboxy kinase (C) Pyruvate kinase (D) Glucose-6-phosphatase
Description : In conversion of Lactic acid to Glucose, three reactions of Glycolytic pathway are circumvented, which of the following enzymes do not participate? (A) Pyruvate Carboxylase (B) Phosphoenol pyruvate carboxy kinase (C) Pyruvate kinase (D) Glucose-6-phosphatase
Last Answer : C
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 : Ethanol decreases gluconeogenesis by (A) Inhibiting glucose-6-phosphatase (B) Inhibiting PEP carboxykinase (C) Converting NAD+ into NADH and decreasing the availability of pyruvate (D) Converting NAD+ into NADH and decreasing the availability of lactate
Description : Which one of the following regulatory actions involves a reversible covalent modification of the enzyme? (A) Phosphorylation of ser-OH on the enzyme (B) Allosteric modulation (C) Competitive inhibition (D) Non-competitive inhibition
Description : Which of the following regulatory reactions involves a reversible covalent modification of an enzyme? (A) Phosphorylation of serine OH on the enzyme (B) Allosteric modulation (C) Competitive inhibition (D) Non-competitive inhibition
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
Description : The 4 rate limiting enzymes of gluconeogenesis are (A) Glucokinase, Pyruvate carboxylae phosphoenol pyruvate carboxykinase and glucose-6-phosphatase (B) Pyruvate carboxylase, phosphoenol ... fructokinase, pyruvate carboxylase, phosphoenol pyruvate carboxykinase and fructose 1, 6 diphosphatase
Last Answer : B
Description : The following is an enzyme required for glycolysis: (A) Pyruvate kinase (B) Pyruvate carboxylase (C) Glucose-6-phosphatase (D) Glycerokinase
Last Answer : A
Description : Covalent modification of an enzyme generally requires a (A) Hormone (B) cAMP (C) Protein kinase (D) All of these
Description : Regulation of some enzymes by covalent modification involves addition or removal of (A) Acetate (B) Sulphate (C) Phosphate (D) Coenzyme
Description : ATP is ‘wasted’ in Rapoport-Lueberring cycle in RBCs as otherwise it will inhibit (A) Phosphoglucomutase (B) Phosphohexo isomerase (C) Phosphofructo kinase (D) Phosphoenol pyruvate carboxy kinase
Description : Allosteric enzymes regulate the formation of products by (A) Feedback inhibition (B) Non-competitive inhibition (C) Competitive inhibition (D) Repression-derepression
Description : cAMD is destroyed by (A) Adenylate cyclase (B) Phosphodiesterase (C) Synthetase phosphatase (D) Synthetase kinase
Description : The first enzyme found to have isoenzymes was (A) Alkaline Phosphatase (B) Lactate dehydrogenase (C) Acid Phosphatase (D) Creatine kinase
Description : In plants, enzyme responsible for the synthesis of the malic acid is : (A) Rubisco (B) PEP carboxylase (C)Kinase (D) Urease
Last Answer : (A) Rubisco
Description : The glycolysis is regulated by (A) Hexokinase (B) Phosphofructokinase (C) Pyruvate kinase (D) All of these
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 : In sugarcane plant 14CO2 is fixed to malic acid, in which the enzyme that fixes CO2 is (a) ribulose biphosphate carboxylase (b) phosphoenol pyruvic acid carboxylase (c) ribulose phosphate kinase (d) fructose phosphatase.
Last Answer : (b) phosphoenol pyruvic acid carboxylase
Description : Glucose-6-phosphate is an allosteric inhibitor of (A) Glucokinase (B) Hexokinase (C) Phosphohexose isomerase (D) None of these
Description : Allosteric activator of glycogen synthase is (A) Glucose (B) Glucose-6-Phosphate (C) UTP (D) Glucose-1-phosphate
Description : Hexokinase is inhibited in an allosteric manner by (A) Glucose-6-Phosphate (B) Glucose-1-Phosphate (C) Fructose-6-phosphate (D) Fructose-1, 6-biphosphate
Description : Glucocorticoids increase the synthesis of all of the following except (A) Glucokinase (B) Glucose-6-phosphatase (C) Fructose-1, 6-biphosphatase (D) Pyruvate carboxylase
Description : The enzyme that converts glucose to glucose-6-phosphate is (A) Phosphatase (B) Hexokinase (C) Phosphorylase (D) Glucose synthetase
Description : Which one of the following enzymes requires a coenzyme derived from the vitamin whose structure is shown below? (A) Enoyl CoA hydratase (B) Phosphofructokinase (C) Glucose-6-phosphatase (D) Glucose-6-phosphate dehydrogenase
Description : The enzyme glucose 6-phosphatase is present in (A) Liver (B) Muscle (C) Adipose tissue (D) Brain
Description : Amylopectinosis is caused due to absence of (A) Debranching enzyme (B) Branching enzyme (C) Acid maltase (D) Glucose-6-phosphatase
Description : Pompe ’s d isease is caused due to deficiency of (A) Lysosomal α-1→4 and 1→6-glucosidase (B) Glucose-6-phosphatase (C) Glycogen synthase (D) Phosphofructokinase
Description : Von Gierke’s disease is characterized by the deficiency of (A) Glucose-6-phosphatase (B) α -1→ 4 Glucosidase (C) 1→ 6 Glucosidase (D) Liver phosphorylase
Description : The enzyme glucose-6-phosphatase which catalyses the conversion of glucose 6-phosphate to glucose is not found in (A) Liver (B) Muscle (C) Intestine (D) Kidney
Description : The hydrolysis of glucose-6-PO4 is catalyzed by a phosphatase that is not found in which of the following? (A) Liver (B) Kidney (C) Muscle (D) Small intestine
Description : The hydrolysis of Glucose-6-P is catalysed by a phosphatase that is not formed in which of the following? (A) Liver (B) Kidney (C) Muscle (D) Small intestine
Description : The hydrolysis of Glucose-6-phosphate is catalysed by a specific phosphatase which is found only in (A) Liver, intestines and kidneys (B) Brain, spleen and adrenals (C) Striated muscle (D) Plasma
Description : The following enzyme is required for the hexose monophosphate shunt pathway: (A) Glucose-6-phosphatase (B) Phosphorylase (C) Aldolase (D) Glucose-6-phosphate dehydrogenase
Description : McArdle’s disease is due to the deficiency of (A) Glucose-6-phosphatase (B) Phosphofructokinase (C) Liver phosphorylase (D) muscle phosphorylase
Description : Glucose-6-phosphatase is absent or deficient in (A) Von Gierke’s disease (B) Pompe’s disease (C) Cori’s disease (D) McArdle’s disease
Description : Glucose-6-phosphatase is not present in (A) Liver and kidneys (B) Kidneys and muscles (C) Kidneys and adipose tissue (D) Muscles and adipose tissue
Description : Conversion of pepsinogen to pepsin is (A) Intra molecular rearrangement (B) Breaking of hydrogen bonds (C) Covalent modification (D) Polymerisation
Description : All the following statements about acetyl CoA carboxylase are true except: (A) It is activated by citrate (B) It is inhibited by palmitoyl CoA (C) It can undergo covalent modification (D) Its dephosphorylated form is inactive
Description : Covalent modification of an enzyme usually involves phosphorylation / dephosphorylation of (A) Serine residue (B) Proline residue (C) Hydroxylysine residue (D) Hydroxyproline residue
Description : Activation or inactivation of certain key regulatory enzymes is accomplished by covalent modification of the amino acid: (A) Tyrosine (B) Phenylalanine (C) Lysine (D) Serine
Description : Give some examples of covalent modification.
Last Answer : Glycogen synthase is inactive, in the phosphorylated state, whereas glycogen phosphorylase is active when phosphorylated.
Description : What is covalent modification?
Last Answer : It means, either addition of a group to the enzyme protein by a covalent bond; or removal of a group by cleaving a covalent bond.
Description : Which one of the following statements concerning glucose metabolism is correct? (A) The conversion of Glucose to lactate occurs only in the R.B.C (B) Glucose enters most cells by a mechanism in ... ) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte
Description : Which one of the following would be expected in pyruvate kinase deficiency? (A) Increased levels of lactate in the R.B.C (B) Hemolytic anemia (C) Decreased ratio of ADP to ATP in R.B.C (D) Increased phosphorylation of Glucose to Glucose-6-phosphate
Description : The following is an enzyme required for glycolysis: (A) Pyruvate kinase (B) Pyruvate carboxylase (C) Glucose-6-phosphatose (D) Glycerokinase