Description : Glucose-6-phosphate is an allosteric inhibitor of (A) Glucokinase (B) Hexokinase (C) Phosphohexose isomerase (D) None of these
Last Answer : Answer : B
Description : The enzymes involved in Phosphorylation of glucose to glucose 6- phosphate are (A) Hexokinase (B) Glucokinase (C) Phosphofructokinase (D) Both (A) and (B)
Last Answer : D
Description : Fructose 2, 3 bi phosphate is a powerful allosteric activator of (A) Fructose 1, 6 diphosphatase (B) Phosphofructokinase (C) Hexokinase (D) Fructokinase
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 : An allosteric inhibitor of pyruvate dehydrogenase is (A) Acetyl CoA (B) ATP (C) NADH (D) Pyruvate
Last Answer : Answer : A
Description : Allosteric inhibitor of glutamate dehydrogenase is (A) ATP (B) ADP (C) AMP (D) GMP
Description : A gluconeogenic enzyme among the following is (A) Phosphofructokinase (B) Pyruvate kinase (C) Phosphoenol pyruvate carboxykinase (D) Glucokinase
Last Answer : Answer : C
Description : A substance unrelated to substrate but capable of reversibly changing activity of enzyme by binding to a site other than active site is called (a) Competitive inhibitor (b) Non-competitive inhibitor (c) Catalytic inhibitor (d) Allosteric modulator/inhibitor
Last Answer : Ans. ((d))
Description : Insulin decreases the synthesis of (A) Hexokinase (B) Glucokinase (C) PEP carboxykinase (D) Glycogen synthetase
Description : During fasting, glucose is phosphorylated mainly by (A) Hexokinase (B) Glucokinase (C) Both (A) and (B) (D) None of these
Description : At low blood glucose concentration, brain but not liver will take up glucose. It is due to the (A) Low Km of hexokinase (B) Low Km of glucokinase (C) Specificity of glucokinase (D) Blood brain barrier
Description : Conversion of glucose to glucose-6- phosphate in human liver is by (A) Hexokinase only (B) Glucokinase only (C) Hexokinase and glucokinase (D) Glucose-6-phosphate dehydrogenase
Description : Hexokinase has a high affinity for glucose than (A) Fructokinase (B) Galactokinase (C) Glucokinase (D) All of the above
Description : The glycolysis is regulated by (A) Hexokinase (B) Phosphofructokinase (C) Pyruvate kinase (D) All of these
Description : Which of the following is an allosteric enzyme? (A) Phosphohexose isomerase (B) Phosphotriose isomerase (C) Lactate dehydrogenase (D) Phosphofructokinase
Last Answer : Answer : D
Description : An example of feedback inhibition is (A) Allosteric inhibition of hexokinase by glucose6-phosphate (B) Cyanide action on cytochrome (C) Sulpha drug on folic acid synthesizer bacteria (D) Reaction between succinic dehydrogenase and succinic acid
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 : Conversion of glucose to glucose-6-phosphate, the first irreversible reaction of glycolysis, is catalysed by (a) phosphofructokinase (b) aldolase (c) hexokinase (d) enolase.
Last Answer : (c) hexokinase
Description : Phosphofructokinase key enzyme in glycolysis is inhibited by (A) Citrate and ATP (B) AMP (C) ADP (D) TMP
Description : Allosteric inhibition (A) Makes active site unifit for substrate (B) Controls excess formation and end product (C) Both (A) and (B) (D) None of these
Description : Enzyme inhibition caused by a substance resembling substrate molecule is (A) Competitive inhibition (B) Non-competitive inhibition (C) Feedback inhibition (D) Allosteric inhibition
Description : The shape of an enzyme and consequently its activity can be reversibly altered from moment to moment by (A) Heat (B) Amino acid substrate (C) Allosteric subunits (D) Sulfur substitutions
Description : Which one of the following statements is not characteristic of allosteric enzymes? (A) They frequently catalyze a committed step early in a metabolic pathway (B) They are often composed of subunits (C) They follow Michaelis-Menten kinetics (D) They frequently show cooperativity for substrate binding
Description : An allosteric enzyme influences the enzyme activity by (A) Competiting for the catalytic site with the substrate (B) Changing the specificity of the enzyme for the substrate (C) Changing the conformation ... binding to a site other than catalytic site (D) Changing the nature of the products formed
Description : An allosteric enzyme is generally inhibited by (A) Initial substrate of the pathway (B) Substrate analogues (C) Product of the reaction catalysed by allosteric enzyme (D) Product of the pathway
Description : AMP is an allosteric inhibitor of (A) PRPP synthetase (B) Adenylosucciante synthetase (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 IMP dehydrogenase is (A) AMP (B) ADP (C) GMP (D) GDP
Description : An allosteric inhibitor of adenylosuccinate synthetase is (A) AMP (B) ADP (C) GMP (D) GDP
Description : An allosteric inhibitor of PRPP glutamyl amido transferase is (A) AMP (B) ADP (C) GMP (D) All of these
Description : Which inactivates an enzyme by occupying its active site? (A) Competitive inhibitor (B) Allosteric inhibitor (C) Non-competitive inhibitor (D) All of these
Description : Which of the following statements about an enzyme exhibiting allosteric kinetics with cooperative interaction is false? (A) A plot of V-Vk [s] has a sigmaidal shape (B) An inhibitor may increase the ... Km and Vmax (D) Removal of allosteric inhibitor may result in hyperbolic V-S [s] plot
Description : Hexokinase (Glucose + ATP → Glucose-6– P + ADP) belongs to the category: (A) Transferases (B) Lysases (C) Oxidoreductases (D) Isomerases
Description : A competitive inhibitor of an enzyme has which of the following properties? (A) It is frequently a feedback inhibitor (B) It becomes covalently attached to an enzyme (C) It decreases the Vmax (D) It interferes with substrate binding to the enzyme
Description : Competitive inhibition can be relieved by raising the (A) Enzyme concentration (B) Substrate concentration (C) Inhibitor concentration (D) None of these
Description : In competitive inhibition, the inhibitor (A) Competes with the enzyme (B) Irreversibly binds with the enzyme (C) Binds with the substrate (D) Competes with the substrate
Description : In competitive enzyme activity inhibition (A) The structure of inhibitor generally resembles that of the substrate (B) Inhibitor decreases apparent Km (C) Km remains unaffective (E) Inhibitor decreases Vmax without affecting Km
Description : In reversible non-competitive enzyme activity inhibition (A) Inhibitor bears structural resemblance to substrate (B) Inhibitor lowers the maximum velocity attainable with a given amount of enzyme (C) Km is increased (D) Km is decreased
Description : Which of the following compound is a positive allosteric modifier of the enzyme pyruvate carboxylase? (A) Biotin (B) Acetyl CoA (C) Oxaloacetate (D) ATP
Last Answer : A
Description : Out of 24 mols of ATP formed in TCA cycle, 2 molecules of ATP can be formed at “substrate level” by which of the following reaction ? (A) Citric acid→ Isocitric acid (B) Isocitrate→ Oxaloacetate (C) Succinic acid→ Fumarate (D) Succinylcat→ Succinic acid
Description : Which one of the following statements regarding enzyme inhibition is correct? (a) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein. (b ... large amount of substrate. (d) Non-competitive inhibitors often bind to the enzyme irreversibly.
Last Answer : (b) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme
Description : Select the option which is not correct with respect to enzyme action. (a) Substrate binds with enzyme at its active site. (b) Addition of lot of succinate does not reverse the inhibition ... from that which binds the substrate. (d) Malonate is a competitive inhibitor of succinic dehydrogenase.
Last Answer : (b) Addition of lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate.
Description : Which one of the following statements is incorrect? (a) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex. (b) The presence of the competitive inhibitor ... . (d) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
Last Answer : (b) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate
Description : A demonstrable inducer is absent in (A) Allosteric enzyme (B) Constitutive enzyme (C) Inhibited enzyme (D) Co-operative enzyme ENZYMES 141
Description : An inducer is absent in the type of enzyme: (A) Allosteric enzyme (B) Constitutive enzyme (C) Co-operative enzyme (D) Isoenzymic enzyme
Description : Enzymes requiring NAD as co-substrate can be assayed by measuring change in absorbance at (A) 210 nm (B) 290 nm (C) 340 nm (D) 365 nm
Description : A sigmoidal plot of substrate concentration ([S]) verses reaction velocity (V) may indicate (A) Michaelis-Menten kinetics (B) Co-operative binding (C) Competitive inhibition (D) Non-competitive inhibition
Description : The ultimate respiratory substrate, yielding maximum number of ATP molecules, is (a) glycogen (b) ketogenic amino acid (c) glucose (d) amylose.
Last Answer : (c) glucose
Description : Oxidative phosphorylation is (a) formation of ATP by transfer of phosphate group from a substrate to ADP (b) oxidation of phosphate group in ATP (c) addition of phosphate group to ATP (d) formation of ATP by energy released from electrons removed during substrate oxidation.
Last Answer : (d) formation of ATP by energy released from electrons removed during substrate oxidation.
Description : In glycolysis, ATP is created by A.photophosphorylation B.the chemiosmotic mechanism C.substrate level phosphorylation D.the pentose phosphate pathway
Last Answer : C.substrate level phosphorylation