The following is a competitive type of enzyme inhibitor: A. Acetazolamide B. Disulfiram C. Physostigmine D. Theophylline

The following is a competitive type of enzyme inhibitor: A. Acetazolamide B. Disulfiram C. Physostigmine D. Theophylline
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C. Physostigmine
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The following is a competitive type of enzyme inhibitor: A. Acetazolamide B. Disulfiram C. Physostigmine D. Theophylline

Description : The following is a competitive type of enzyme inhibitor: A. Acetazolamide B. Disulfiram C. Physostigmine D. Theophylline

Last Answer : C. Physostigmine

The following inhibitor binds only to the ani-onic site of the cholinesterase enzyme: A. Neostigmine B. Physostigmine C. Edrophonium D. Dyflos

Description : The following inhibitor binds only to the ani-onic site of the cholinesterase enzyme: A. Neostigmine B. Physostigmine C. Edrophonium D. Dyflos

Last Answer : C. Edrophonium

Physostigmine is a competitive inhibitor of (A) Xanthine oxidase (B) Cholinesterase (C) Carbonic anhydrase (D) Monoamine oxidase

Description : Physostigmine is a competitive inhibitor of (A) Xanthine oxidase (B) Cholinesterase (C) Carbonic anhydrase (D) Monoamine oxidase

Last Answer : Answer : B

Which of the following is a specific inhibitor of the enzyme alcohol dehydrogenase and is useful in the treatment of methanol poisoning: A. Disulfiram B. Ethylene glycol C. Calcium leucovorin D. Fomepizole

Description : Which of the following is a specific inhibitor of the enzyme alcohol dehydrogenase and is useful in the treatment of methanol poisoning: A. Disulfiram B. Ethylene glycol C. Calcium leucovorin D. Fomepizole

Last Answer : D. Fomepizole

Reactivation of cholinesterase enzyme occurs on hydrolysis of the inhibitor by the same enzyme molecule in case of the following anticholinesterase: A. Edrophonium B. Neostigmine C. Dyflos D. Tacrine

Description : Reactivation of cholinesterase enzyme occurs on hydrolysis of the inhibitor by the same enzyme molecule in case of the following anticholinesterase: A. Edrophonium B. Neostigmine C. Dyflos D. Tacrine

Last Answer : B. Neostigmine

Neostigmine is preferred over physostigmine for treating myasthenia gravis because: A. It is better absorbed orally B. It has longer duration of action C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate D. It penetrates blood-brain barrier

Description : Neostigmine is preferred over physostigmine for treating myasthenia gravis because: A. It is better absorbed orally B. It has longer duration of action C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate D. It penetrates blood-brain barrier

Last Answer : C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate

The following inhibitor binds only to the ani-onic site of the cholinesterase enzyme: A. Neostigmine B. Physostigmine C. Edrophonium D. Dyflos

Description : The following inhibitor binds only to the ani-onic site of the cholinesterase enzyme: A. Neostigmine B. Physostigmine C. Edrophonium D. Dyflos

Last Answer : C. Edrophonium

Select the drug that undergoes extensive first-pass metabolism in the liver: A. Phenobarbitone B. Propranolol C. Phenylbutazone D. Theophylline

Description : Select the drug that undergoes extensive first-pass metabolism in the liver: A. Phenobarbitone B. Propranolol C. Phenylbutazone D. Theophylline

Last Answer : B. Propranolol

Select the drug that undergoes extensive first-pass metabolism in the liver: A. Phenobarbitone B. Propranolol C. Phenylbutazone D. Theophylline

Description : Select the drug that undergoes extensive first-pass metabolism in the liver: A. Phenobarbitone B. Propranolol C. Phenylbutazone D. Theophylline

Last Answer : B. Propranolol

Identify one of the canbonic anhydrase inhibitor that inhibit only luminal carbonic anhydrase enzyme. (A) Methazolamide (B) Acetazolamide (C) Dichlorphenamide(D) Benzolamide

Description : Identify one of the canbonic anhydrase inhibitor that inhibit only luminal carbonic anhydrase enzyme. (A) Methazolamide (B) Acetazolamide (C) Dichlorphenamide(D) Benzolamide

Last Answer : Answer : B

The following is a competitive antagonist of GABA but a noncompetitive antagonist of diazepam: A. Picrotoxin B. Muscimol C. Flumazenil D. Bicuculline

Description : The following is a competitive antagonist of GABA but a noncompetitive antagonist of diazepam: A. Picrotoxin B. Muscimol C. Flumazenil D. Bicuculline

Last Answer : D. Bicuculline

The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor

Description : The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor

Last Answer : C. Suppression of maximal agonist response

A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Description : A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Last Answer : C. Noncompetitive antagonist

A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Description : A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Last Answer : C. Competitive antagonist

Drugs acting through receptors exhibit the following features except: A. Structural specificity B. High potency C. Competitive antagonism D. Dependence of action on lipophilicity

Description : Drugs acting through receptors exhibit the following features except: A. Structural specificity B. High potency C. Competitive antagonism D. Dependence of action on lipophilicity

Last Answer : D. Dependence of action on lipophilicity

The following is a competitive antagonist of GABA but a noncompetitive antagonist of diazepam: A. Picrotoxin B. Muscimol C. Flumazenil D. Bicuculline

Description : The following is a competitive antagonist of GABA but a noncompetitive antagonist of diazepam: A. Picrotoxin B. Muscimol C. Flumazenil D. Bicuculline

Last Answer : D. Bicuculline

The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor

Description : The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor

Last Answer : C. Suppression of maximal agonist response

A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Description : A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Last Answer : C. Noncompetitive antagonist

A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Description : A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Last Answer : C. Competitive antagonist

The following statement is not true of log dose-response curve: A. It is almost linear except at the ends B. It is a rectangular hyperbola C. It facilitates comparison of different agonists D. It can help in discriminating between competitive and noncompetitive antagonists

Description : The following statement is not true of log dose-response curve: A. It is almost linear except at the ends B. It is a rectangular hyperbola C. It facilitates comparison of different agonists D. It can help in discriminating between competitive and noncompetitive antagonists

Last Answer : B. It is a rectangular hyperbola

Drugs acting through receptors exhibit the following features except: A. Structural specificity B. High potency C. Competitive antagonism D. Dependence of action on lipophilicity

Description : Drugs acting through receptors exhibit the following features except: A. Structural specificity B. High potency C. Competitive antagonism D. Dependence of action on lipophilicity

Last Answer : D. Dependence of action on lipophilicity

What happens to an enzyme when a competitive inhibitor binds to it?

Description : What happens to an enzyme when a competitive inhibitor binds to it?

Last Answer : Need answer

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 inactivates an enzyme by occupying its active site? (A) Competitive inhibitor (B) Allosteric inhibitor (C) Non-competitive inhibitor (D) All of these

Last Answer : Answer : A

A competitive inhibitor of an enzyme (A) Increases Km without affecting Vmax (B) Decreases Km without affecting Vmax (C) Increases Vmax without affecting Km (D) Decreases both Vmax and Km

Description : A competitive inhibitor of an enzyme (A) Increases Km without affecting Vmax (B) Decreases Km without affecting Vmax (C) Increases Vmax without affecting Km (D) Decreases both Vmax and Km

Last Answer : Answer : A

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 : 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

Last Answer : Answer : D

Competitive inhibition can be relieved by raising the (A) Enzyme concentration (B) Substrate concentration (C) Inhibitor concentration (D) None of these

Description : Competitive inhibition can be relieved by raising the (A) Enzyme concentration (B) Substrate concentration (C) Inhibitor concentration (D) None of these

Last Answer : Answer : B

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 inhibition, the inhibitor (A) Competes with the enzyme (B) Irreversibly binds with the enzyme (C) Binds with the substrate (D) Competes with the substrate

Last Answer : Answer : D

In non competitive enzyme activity inhibition, inhibitor (A) Increases Km (B) Decreases Km (C) Does not effect Km (D) Increases Km

Description : In non competitive enzyme activity inhibition, inhibitor (A) Increases Km (B) Decreases Km (C) Does not effect Km (D) Increases Km

Last Answer : Answer : C

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 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

Last Answer : Answer : A

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 : 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

Last Answer : Answer : B

The kinetic effect of purely competitive inhibitor of an enzyme (A) Increases Km without affecting Vmax (B) Decreases Km without affecting Vmax (C) Increases Vmax without affecting Km (D) Decreases Vmax without affecting Km

Description : The kinetic effect of purely competitive inhibitor of an enzyme (A) Increases Km without affecting Vmax (B) Decreases Km without affecting Vmax (C) Increases Vmax without affecting Km (D) Decreases Vmax without affecting Km

Last Answer : Answer : A

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

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))

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) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme. (c) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate. (d) Non-competitive inhibitors often bind to the enzyme irreversibly.

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

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 of succinic dehydrogenase by malonate. (c) A non-competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate. (d) Malonate is a competitive inhibitor of succinic dehydrogenase.

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.

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 decreases the Km of the enzyme for the substrate. (c) A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex. (d) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.

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

In the synthetic pathway of epinephrine, disulfiram (antabuse) inhibits the enzyme: (A) Tyrosine hydroxylase (B) Dopamine β-hydroxylase (C) DOPA decarboxylase (D) N-methyl transferase

Description : In the synthetic pathway of epinephrine, disulfiram (antabuse) inhibits the enzyme: (A) Tyrosine hydroxylase (B) Dopamine β-hydroxylase (C) DOPA decarboxylase (D) N-methyl transferase

Last Answer : Answer : B

Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of hepatocytes C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein

Description : Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of ... C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein

Last Answer : D. Increased synthesis of enzyme protein

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 acetylcholine B. Regeneration time of the phosphorylated enzyme is longer than the turnover time of the enzyme molecules C. Phosphorylation results in rapid degradation of enzyme molecules D. They are neither metabolized nor excreted from the body

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

The anticholinesterase action of edrophonium is short lasting because termination of its action depends on: A. Dissociation and diffusion of the drug from the enzyme B. Hydrolysis of the drug by the enzyme C. Synthesis of fresh enzyme molecules D. A combination of the above three processes

Description : The anticholinesterase action of edrophonium is short lasting because termination of its action depends on: A. Dissociation and diffusion of the drug from the enzyme B. Hydrolysis of the drug by the enzyme C. Synthesis of fresh enzyme molecules D. A combination of the above three processes

Last Answer : A. Dissociation and diffusion of the drug from the enzyme

Which of the following drugs acts by inhibiting an enzyme in the body: A. Atropine B. Allopurinol C. Levodopa D. Metoclopramide

Description : Which of the following drugs acts by inhibiting an enzyme in the body: A. Atropine B. Allopurinol C. Levodopa D. Metoclopramide

Last Answer : B. Allopurinol

Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of hepatocytes C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein

Description : Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of ... C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein

Last Answer : D. Increased synthesis of enzyme protein

Microsomal enzyme induction can be a cause of: A. Tolerance B. Physical dependence C. Psychological dependence D. Idiosyncrasy

Description : Microsomal enzyme induction can be a cause of: A. Tolerance B. Physical dependence C. Psychological dependence D. Idiosyncrasy

Last Answer : A. Tolerance

Choose the correct statement about lovastatin: A. It markedly lowers plasma triglyceride with little effect on cholesterol level B. It is used as an adjuvant to gemfibrozil for type III hyperlipoproteinemia C. It is not effective in diabetes associated hypercholesterolemia D. It is a competitive inhibitor of the rate limiting step in cholesterol synthesis

Description : Choose the correct statement about lovastatin: A. It markedly lowers plasma triglyceride with little effect on cholesterol level B. It is used as an adjuvant to gemfibrozil for type III ... hypercholesterolemia D. It is a competitive inhibitor of the rate limiting step in cholesterol synthesis

Last Answer : D. It is a competitive inhibitor of the rate limiting step in cholesterol synthesis

Intradermal drug sensitivity tests can detect the presence of following type of hypersensitivity: A. Type I (anaphylactic) B. Type II (cytolytic) C. Type III (retarded) D. All of the above

Description : Intradermal drug sensitivity tests can detect the presence of following type of hypersensitivity: A. Type I (anaphylactic) B. Type II (cytolytic) C. Type III (retarded) D. All of the above

Last Answer : A. Type I (anaphylactic)

The type II, type III and type IV hypersensitivity reactions can be suppressed by: A. Adrenaline B. Antihistaminics C. Corticosteroids D. Sod. cromoglycate

Description : The type II, type III and type IV hypersensitivity reactions can be suppressed by: A. Adrenaline B. Antihistaminics C. Corticosteroids D. Sod. cromoglycate

Last Answer : C. Corticosteroids

Which of the following is a type B (unpredictable) adverse drug reaction: A. Side effect B. Toxic effect C. Idiosyncrasy D. Physical dependence

Description : Which of the following is a type B (unpredictable) adverse drug reaction: A. Side effect B. Toxic effect C. Idiosyncrasy D. Physical dependence

Last Answer : A. Side effect

Intradermal drug sensitivity tests can detect the presence of following type of hypersensitivity: A. Type I (anaphylactic) B. Type II (cytolytic) C. Type III (retarded) D. All of the above

Description : Intradermal drug sensitivity tests can detect the presence of following type of hypersensitivity: A. Type I (anaphylactic) B. Type II (cytolytic) C. Type III (retarded) D. All of the above

Last Answer : A. Type I (anaphylactic)

The type II, type III and type IV hypersensitivity reactions can be suppressed by: A. Adrenaline B. Antihistaminics C. Corticosteroids D. Sod. cromoglycate

Description : The type II, type III and type IV hypersensitivity reactions can be suppressed by: A. Adrenaline B. Antihistaminics C. Corticosteroids D. Sod. cromoglycate

Last Answer : C. Corticosteroids

Which of the following is a type B (unpredictable) adverse drug reaction: A. Side effect B. Toxic effect C. Idiosyncrasy D. Physical dependence

Description : Which of the following is a type B (unpredictable) adverse drug reaction: A. Side effect B. Toxic effect C. Idiosyncrasy D. Physical dependence

Last Answer : C. Idiosyncrasy

The following receptor type has 7 helical membrane spanning amino acid segments with 3 extracellular and 3 intracellular loops: A. Tyrosine protein kinase receptor B. Gene expression regulating receptor C. Intrinsic ion channel containing receptor D. G protein coupled receptor

Description : The following receptor type has 7 helical membrane spanning amino acid segments with 3 extracellular and 3 intracellular loops: A. Tyrosine protein kinase receptor B. Gene expression regulating receptor C. Intrinsic ion channel containing receptor D. G protein coupled receptor

Last Answer : D. G protein coupled receptor