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

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

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

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

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

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

Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its: A. Shorter duration of action B. Longer duration of action C. Direct action on muscle end-plate D. Selective inhibition of true cholinesterase

Description : Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its: A. Shorter duration of action B. Longer duration of action C. Direct action on muscle end-plate D. Selective inhibition of true cholinesterase

Last Answer : A. Shorter duration of action

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 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

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

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

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.

Pseudocholinesterase differs from true cholinesterase in that: A. It does not hydrolyse acetylcholine B. It hydrolyses acetylcholine at a slower rate C. It is more susceptible to inhibition by physostigmine D. It is the only form of circulating cholinesterase

Description : Pseudocholinesterase differs from true cholinesterase in that: A. It does not hydrolyse acetylcholine B. It hydrolyses acetylcholine at a slower rate C. It is more susceptible to inhibition by physostigmine D. It is the only form of circulating cholinesterase

Last Answer : B. It hydrolyses acetylcholine at a slower rate

Pseudocholinesterase differs from true cholinesterase in that: A. It does not hydrolyse acetylcholine B. It hydrolyses acetylcholine at a slower rate C. It is more susceptible to inhibition by physostigmine D. It is the only form of circulating cholinesterase

Description : Pseudocholinesterase differs from true cholinesterase in that: A. It does not hydrolyse acetylcholine B. It hydrolyses acetylcholine at a slower rate C. It is more susceptible to inhibition by physostigmine D. It is the only form of circulating cholinesterase

Last Answer : B. It hydrolyses acetylcholine at a slower rate

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

Pyridostigmine differs from neostigmine in that: A. It is more potent orally B. It is longer acting C. It produces less muscarinic side effects D. It does not have any direct action on NM receptors

Description : Pyridostigmine differs from neostigmine in that: A. It is more potent orally B. It is longer acting C. It produces less muscarinic side effects D. It does not have any direct action on NM receptors

Last Answer : B. It is longer acting

The mechanism by which neostigmine improves contraction of myasthenic muscle involves: A. Repetitive binding of the acetylcholine molecules to the same receptors at the muscle endplate B. Diffusion of acetylcholine released from motor nerve endings to a wider area activating neighbouring receptors C. Activation of motor end-plate receptors by neostigmine molecules themselves D. All of the above

Description : The mechanism by which neostigmine improves contraction of myasthenic muscle involves: A. Repetitive binding of the acetylcholine molecules to the same receptors at the muscle endplate B. Diffusion of ... Activation of motor end-plate receptors by neostigmine molecules themselves D. All of the above

Last Answer : D. All of the above

Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its: A. Shorter duration of action B. Longer duration of action C. Direct action on muscle end-plate D. Selective inhibition of true cholinesterase

Description : Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its: A. Shorter duration of action B. Longer duration of action C. Direct action on muscle end-plate D. Selective inhibition of true cholinesterase

Last Answer : A. Shorter duration of action

The most effective antidote for belladonna poisoning is (a) Neostigmine (b) Physostigmine (c) Pilocarpine (d) Methacholine

Description : The most effective antidote for belladonna poisoning is (a) Neostigmine (b) Physostigmine (c) Pilocarpine (d) Methacholine

Last Answer : Ans: B

Which of the following agents is a prodrug that is much less toxic in mammals than in insects ? (a) Acetylcholine (b) Bethanechol (c) Physostigmine (d) Pilocarpine (e) Neostigmine

Description : Which of the following agents is a prodrug that is much less toxic in mammals than in insects ? (a) Acetylcholine (b) Bethanechol (c) Physostigmine (d) Pilocarpine (e) Neostigmine

Last Answer : Ans: C

A direct-acting cholinomimetic that is lipid-soluble and often used in the treatment of glaucoma is (a) Acetylcholine (b) Bethanechol (c) Physostigmine (d) Pilocarpine (e) Neostigmine

Description : A direct-acting cholinomimetic that is lipid-soluble and often used in the treatment of glaucoma is (a) Acetylcholine (b) Bethanechol (c) Physostigmine (d) Pilocarpine (e) Neostigmine

Last Answer : Ans: D

The most effective antidote for belladonna poisoning is: A. Neostigmine B. Physostigmine C. Pilocarpine D. Methacholine

Description : The most effective antidote for belladonna poisoning is: A. Neostigmine B. Physostigmine C. Pilocarpine D. Methacholine

Last Answer : B. Physostigmine

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 most effective antidote for belladonna poisoning is: A. Neostigmine B. Physostigmine C. Pilocarpine D. Methacholine

Description : The most effective antidote for belladonna poisoning is: A. Neostigmine B. Physostigmine C. Pilocarpine D. Methacholine

Last Answer : B. Physostigmine

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

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

Neostigmine is beneficial in cobra envenomation because: A. It binds to and inactivates cobra toxin B. It reverses coma due to cobra toxin C. It counteracts the cardio-depressant action of cobra toxin D. It antagonizes the paralysing action of cobra toxin

Description : Neostigmine is beneficial in cobra envenomation because: A. It binds to and inactivates cobra toxin B. It reverses coma due to cobra toxin C. It counteracts the cardio-depressant action of cobra toxin D. It antagonizes the paralysing action of cobra toxin

Last Answer : D. It antagonizes the paralysing action of cobra toxin

Neostigmine is beneficial in cobra envenomation because: A. It binds to and inactivates cobra toxin B. It reverses coma due to cobra toxin C. It counteracts the cardio-depressant action of cobra toxin D. It antagonizes the paralysing action of cobra toxin

Description : Neostigmine is beneficial in cobra envenomation because: A. It binds to and inactivates cobra toxin B. It reverses coma due to cobra toxin C. It counteracts the cardio-depressant action of cobra toxin D. It antagonizes the paralysing action of cobra toxin

Last Answer : D. It antagonizes the paralysing action of cobra toxin

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

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

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

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

The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Description : The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Last Answer : C. Lipid solubility of the drug

The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Description : The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Last Answer : C. Lipid solubility of the drug

The site of action of miotics for therapeutic effect in angle closure glaucoma is: A. Canal of Schlemm B. Ciliary body C. Ciliary muscle D. Sphincter pupillae muscle

Description : The site of action of miotics for therapeutic effect in angle closure glaucoma is: A. Canal of Schlemm B. Ciliary body C. Ciliary muscle D. Sphincter pupillae muscle

Last Answer : D. Sphincter pupillae muscle

The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Description : The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation

Last Answer : C. Lipid solubility of the drug

Platelets contain an enzyme which has important role in clotting in blood. This enzyme is known as (A) Cholinesterase (B) Transaminase (C) Decarboxylase (D) Thrombokinase

Description : Platelets contain an enzyme which has important role in clotting in blood. This enzyme is known as (A) Cholinesterase (B) Transaminase (C) Decarboxylase (D) Thrombokinase

Last Answer : Answer : D

Following enzyme is involved in the synthesis of actylcholine (a) Choline acetyl transferase (b) Acetyl cholinesterase (c) Both (a) and (b) (d) None of the above

Description : Following enzyme is involved in the synthesis of actylcholine (a) Choline acetyl transferase (b) Acetyl cholinesterase (c) Both (a) and (b) (d) None of the above

Last Answer : Ans: A

Pralidoxime can reactivate cholinesterase enzyme that has been inactivated by: A. Carbamate anticholinesterases B. Organophosphate anticholinesterases C. Both carbamate and organophosphate anticholinesterases D. Reversible anticholinesterases

Description : Pralidoxime can reactivate cholinesterase enzyme that has been inactivated by: A. Carbamate anticholinesterases B. Organophosphate anticholinesterases C. Both carbamate and organophosphate anticholinesterases D. Reversible anticholinesterases

Last Answer : B. Organophosphate anticholinesterases

Pralidoxime can reactivate cholinesterase enzyme that has been inactivated by: A. Carbamate anticholinesterases B. Organophosphate anticholinesterases C. Both carbamate and organophosphate anticholinesterases D. Reversible anticholinesterases

Description : Pralidoxime can reactivate cholinesterase enzyme that has been inactivated by: A. Carbamate anticholinesterases B. Organophosphate anticholinesterases C. Both carbamate and organophosphate anticholinesterases D. Reversible anticholinesterases

Last Answer : B. Organophosphate anticholinesterases

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 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

Following statements describe the characteristics of the enzyme restriction endonuclease. Identify the incorrect statement. (a) The enzyme recognises a specific palindromic nucleotide sequence in the DNA. (b) The enzyme cuts DNA molecule at identified position within the DNA. (c) The enzyme binds DNA at specific sites and cuts only one of the two strands. (d) The enzyme cuts the sugar-phosphate backbone at specific sites on each strand.

Description : Following statements describe the characteristics of the enzyme restriction endonuclease. Identify the incorrect statement. (a) The enzyme recognises a specific palindromic nucleotide sequence in the DNA. (b) ... (d) The enzyme cuts the sugar-phosphate backbone at specific sites on each strand.

Last Answer : (c) The enzyme binds DNA at specific sites and cuts only one of the two strands.

Which one of the following statements regarding a catalyst is not correct? A An enzyme is a catalyst that only binds certain substrates. B An enzyme is a protein that is a highly efficient catalyst for one or more chemical reactions in a living system. C Catalysts increase the rate of a reaction by altering the mechanism, thereby increasing the activation energy. D Catalysts do not alter the equilibrium constant for a chemical reaction.

Description : Which one of the following statements regarding a catalyst is not correct? A An enzyme is a catalyst that only binds certain substrates. B An enzyme is a protein that is a highly ... increasing the activation energy. D Catalysts do not alter the equilibrium constant for a chemical reaction.

Last Answer : C Catalysts increase the rate of a reaction by altering the mechanism, thereby increasing the activation energy.

Which of the following is the only life saving measure in case of anaphylactic shock: A. Intravenous hydrocortisone hemisuccinate B. Intravenous chlorpheniramine maleate C. Intramuscular adrenaline hydrochloride D. Intravenous glucose-saline

Description : Which of the following is the only life saving measure in case of anaphylactic shock: A. Intravenous hydrocortisone hemisuccinate B. Intravenous chlorpheniramine maleate C. Intramuscular adrenaline hydrochloride D. Intravenous glucose-saline

Last Answer : C. Intramuscular adrenaline hydrochloride

Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an ‘all or none’ action on a receptor C. Receptor and drugs acting on it have rigid complementary ‘lock and key’ structural features D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable

Description : Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an all or none' action on a ... lock and key' structural features D. Properties of affinity' and intrinsic activity' are independently variable

Last Answer : D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable

Muscarinic cholinergic receptors: A. Are located only on parasympathetically innervated effector cells B. Mediate responses by opening an intrinsic Na+ ion channel C. Are present on vascular endothelium which has no cholinergic nerve supply D. Predominate in the autonomic ganglia

Description : Muscarinic cholinergic receptors: A. Are located only on parasympathetically innervated effector cells B. Mediate responses by opening an intrinsic Na+ ion channel C. Are present on vascular endothelium which has no cholinergic nerve supply D. Predominate in the autonomic ganglia

Last Answer : C. Are present on vascular endothelium which has no cholinergic nerve supply

Which of the following is the only life saving measure in case of anaphylactic shock: A. Intravenous hydrocortisone hemisuccinate B. Intravenous chlorpheniramine maleate C. Intramuscular adrenaline hydrochloride D. Intravenous glucose-saline

Description : Which of the following is the only life saving measure in case of anaphylactic shock: A. Intravenous hydrocortisone hemisuccinate B. Intravenous chlorpheniramine maleate C. Intramuscular adrenaline hydrochloride D. Intravenous glucose-saline

Last Answer : C. Intramuscular adrenaline hydrochloride

Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an ‘all or none’ action on a receptor C. Receptor and drugs acting on it have rigid complementary ‘lock and key’ structural features D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable

Description : Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an all or none' action on a ... lock and key' structural features D. Properties of affinity' and intrinsic activity' are independently variable

Last Answer : D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable