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
Last Answer : Answer : C
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
Last Answer : Answer : A
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 : 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 : Allosteric enzymes regulate the formation of products by (A) Feedback inhibition (B) Non-competitive inhibition (C) Competitive inhibition (D) Repression-derepression
Description : Allosteric inhibition is also known as (A) Competitive inhibition (B) Non-competitive inhibition (C) Feedback inhibition (D) None of these
Description : An example of enzyme inhibition: (A) Reversible inhibition (B) Irreversible inhibition (C) Allosteric inhibition (D) All of these ENZYMES 151
Last Answer : Answer : D
Description : Give examples for allosteric inhibition.
Last Answer : ALA synthase, aspartyl trans-carbamoylase, HMG CoA reductase
Description : What are the salient features of allosteric inhibition?
Last Answer : (1) The inhibitor is not a substrate analogue. (2) It is partially reversible when excess substrate is added. (3) Km is usually increased. (4) Vmax is reduced. (5) Most allosteric enzymes possess quaternary structure. They are made up of subunits.
Description : Difference between competitive and allosteric inhibition -Biology
Last Answer : answer:
Description : The sulfa drugs work by _______ with PABA in making folic acid. a. Positive Feedback b. Negative Feedback c. Competitive Inhibition d. Allosteric Inhibition
Last Answer : c. Competitive Inhibition
Description : Negative regulation of protein synthesis is accomplished by A- allosteric inhibition B- the binding of RNA polymerase to the promoter C- the binding of a repressor to the DNA D- the binding of a repressor to the RNA polymerase
Last Answer : the binding of a repressor to the DNA
Description : The organophosphates produce irreversible inhibition of cholinesterase because: A. They bind to an allosteric site of the enzyme resulting in unfavourable conformation of esteratic site to bind ... degradation of enzyme molecules D. They are neither metabolized nor excreted from the body
Last Answer : B. Regeneration time of the phosphorylated enzyme is longer than the turnover time of the enzyme molecules
Description : The following abnormality in PRPP synthetase can cause primary gout: (A) High Vmax (B) Low Km (C) Resistance to allosteric inihbition. (D) All of these
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 : 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 : An enzyme of pyrimidine nucleotide biosynthesis sensitive to allosteric regulation is (A) Aspartate transcarbamoylase (B) Dihydroorotase (C) Dihydroorotate dehydrogenase (D) Orotidylic acid decarboxylase
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 : Regulation of haem synthesis occurs by (A) Covalent modification (B) Repression - derepression (C) Induction (D) Allosteric regulation
Last Answer : Answer : B
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 : Allosteric enzymes contain (A) Multiple subunits (B) Single chain (C) Two chains (D) Three chains
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 : In which of the following types of enzymes an inducer is not required? (A) Inhibited enzyme (B) Cooperative enzyme (C) Allosteric enzyme (D) Constitutive enzyme
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 : 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 : Fructose 2, 3 bi phosphate is a powerful allosteric activator of (A) Fructose 1, 6 diphosphatase (B) Phosphofructokinase (C) Hexokinase (D) Fructokinase
Description : Glucose-6-phosphatase and PEP carboxy kinase are regulated by (A) Covalent modification (B) Allosteric regulation (C) Induction and repression (D) All of these
Description : ATP is a co-substrate as well as an allosteric inhibitor of (A) Phosphofructokinase (B) Hexokinase (C) Glucokinase (D) None of these
Description : Glucose-6-phosphate is an allosteric inhibitor of (A) Glucokinase (B) Hexokinase (C) Phosphohexose isomerase (D) None of these
Description : Which of the following is an allosteric enzyme? (A) Phosphohexose isomerase (B) Phosphotriose isomerase (C) Lactate dehydrogenase (D) Phosphofructokinase
Description : All of the following are allosteric enzymes except (A) Citrate synthetase (B) a-Ketoglutarate dehdrogenase (C) Succinate thiokinase (D) Succinate dehydrogenase
Description : An allosteric inhibitor of pyruvate dehydrogenase is (A) Acetyl CoA (B) ATP (C) NADH (D) Pyruvate
Description : Pyruvate dehydrogenase complex is regulated by (A) Covalent modification (B) Allosteric regulation (C) Both (A) and (B) (D) None of these
Description : Kinetics of an allosteric enzyme are explained by (A) Michaelis-Menten equation (B) Lineweaver-Burk plot (C) Hill plot (D) All of these
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 : In gluconeogensis, an allosteric activator required in the synthesis of oxaloacetate from bicarbonate and pyruvate, which is catalysed by the enzyme pyruvate carboxylase is (A) Acetyl CoA (B) Succinate (C) Isocitrate (D) Citrate
Description : Allosteric activator of glycogen synthase is (A) Glucose (B) Glucose-6-Phosphate (C) UTP (D) Glucose-1-phosphate
Description : The rate of citric acid cycle is controlled by the allosteric enzyme: (A) Aconitase (B) Fumarase (C) Fumarase (D) Malate dehydrogenase
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 : 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 : 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
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