Description : An example of competitive inhibition of an enzyme is the inhibition of a. Succinic dehydrogenase by malonic acid b. Cytochrome oxidase by cyanide c. Hexokinase by glucose-6-phosphate d. Carbonic anhydrase by carbon dioxide
Last Answer : Ans: A
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 : Example of an extracellular enzyme is (A) Lactate dehydrogenase (B) Cytochrome oxidase (C) Pancreatic lipase (D) Hexokinase
Last Answer : Answer : C
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 : Copper is associated with _____ mitochondria' enzymes. (1) Cytochrome oxidase (2) Succinic dehydrogenase (3) Catalase (4) Acid phosphatase
Last Answer : (1) Cytochrome oxidase Explanation: Copper is involved in normalized function of many enzymes, such as cytochrome oxidase, which is complex IV in mitochondrial electron ... transportation, antioxidant and free radical scavenging and neutralization, and neurotransmitter synthesis, respectively.
Description : Copper is associated with ____ mitochondrial enzymes. (1) Cytochrome oxidase (2) Succinic dehydrogenase (3) Catalase (4) Acid phosphatase
Last Answer : Cytochrome oxidase
Description : Fructose 2, 3 bi phosphate is a powerful allosteric activator of (A) Fructose 1, 6 diphosphatase (B) Phosphofructokinase (C) Hexokinase (D) Fructokinase
Last Answer : Answer : B
Description : Glucose-6-phosphate is an allosteric inhibitor of (A) Glucokinase (B) Hexokinase (C) Phosphohexose isomerase (D) None of these
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
Last Answer : Answer : A
Description : Sulpha drugs are antimetabolities of (A) Vitamin K (B) Pyridoxin (C) Folic acid (D) Vitamin B2
Description : The hexose monophosphate pathway includes the enzyme: (A) Maltase dehydrogenase (B) Hexokinase (C) α-Ketoglutarate dehydrogenase (D) Glucose-6-phosphate dehydrogenase
Last Answer : Answer : D
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
Last Answer : C
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 : 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 : The inhibition of succinate dehydrogenase by malonate by (A) Competitive inhibition (B) Non-competitive inhibition (C) Uncompetitive inhibition (D) Feedback inhibition
Description : The best example of extracellular enzymes (exoenzyme) is (A) Nucleases (B) Digestive enzymes (C) Succinic dehydrogenase (D) None 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 : An example of enzyme inhibition: (A) Reversible inhibition (B) Irreversible inhibition (C) Allosteric inhibition (D) All of these ENZYMES 151
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 : The rate of citric acid cycle is controlled by the allosteric enzyme: (A) Aconitase (B) Fumarase (C) Fumarase (D) Malate dehydrogenase
Description : A mitochondrial marker enzyme is (A) Aldolase (B) Amylase (C) Succinic dehydrogenase (D) Pyruvate dehydrogenase ENZYMES 175
Description : Infant i le convu ls ions due to lesser formation of gamma amino butyric acid from glutamic acid is seen in the deficiency of (A) Glutamate-dehydrogenase (B) Pyridoxine (C) Folic acid (D) Thiamin
Description : The distinctive features of azithromycin include the following except: A. Efficacy against organisms which have developed resistance to erythromycin B. Marked tissue distribution and intracellular penetration ... D. Low propensity to drug interactions due to inhibition of cytochrome P450 enzymes
Last Answer : A. Efficacy against organisms which have developed resistance to erythromycin
Description : Activity of cytochrome oxidase is inhibited by (A) Sulphite (B) Sulphate (C) Arsenite (D) Cyanide
Description : Conversion of fructose to sorbitol is catalysed by the enzyme: (A) Sorbitol dehydrogenase (B) Aldose reductase (C) Fructokinase (D) Hexokinase
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 : Feedback inhibition of enzyme action is affected by (A) Enzyme (B) Substrate (C) End products (D) None of these
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 : 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 : 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 : What is allosteric inhibition?
Last Answer : Allosteric enzyme has one catalytic site where the substrate binds and another separate allosteric site where the modifier binds.
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 : 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 : 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 : Allosteric inhibitor of glutamate dehydrogenase is (A) ATP (B) ADP (C) AMP (D) GMP
Description : An allosteric enzyme responsible for controlling the rate of T.C.A cycle is (A) Malate dehydrogenase (B) Isocitrate dehydrogenase (C) Fumarase (D) Aconitase
Last Answer : B
Description : The principal action of insulin in adipose tissue is to inhibit the activity of the (A) Hormone sensitive lipoprotein lipase (B) Glycerol phosphate acyltransferase (C) Acetyl-CoA carboxylase (D) Pyruvate dehydrogenase
Description : Both folic acid and methyl cobalamin (vitamin B12) are required in (A) Deamination of serine (B) Deamination of threonine (C) Conversion of pyridoxal phosphate to pyridoxamine phosphate (D) Methylation of homocystein to methionine
Description : A specific inhibitor for succinate dehydrogenase is (A) Arsinite (B) Melouate (C) Citrate (D) Cyanide
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 : The enzyme that converts glucose to glucose-6-phosphate is (A) Phosphatase (B) Hexokinase (C) Phosphorylase (D) Glucose synthetase
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 : The enzyme using some other substance, not oxygen as hydrogen acceptor is (A) Tyrosinase (B) Succinate dehydrogenase (C) Uricase (D) Cytochrome oxidase