‘Lock’ and ‘Key’ model of enzyme action proposed by Fisher implies that (A) The active site is flexible and adjusts to substrate (B) The active site requires removal of PO4 group (C) The active site is complementary in shape to that of the substrate (D) Substrates change conformation prior to active site interaction

‘Lock’ and ‘Key’ model of enzyme action proposed by Fisher implies that (A) The active site is flexible and adjusts to substrate (B) The active site requires removal of PO4 group (C) The active site is complementary in shape to that of the substrate (D) Substrates change conformation prior to active site interaction
by

1 Answer

Answer :

Answer :  C
by
selected

Related questions

Fischer’s ‘lock and key’ model of the enzyme action implies that (A) The active site is complementary in shape to that of substance only after interaction. (B) The active site is complementary in shape to that of substance (C) Substrates change conformation prior to active site interaction (D) The active site is flexible and adjusts to substrate

Description : Fischer's lock and key' model of the enzyme action implies that (A) The active site is complementary in shape to that of substance only after interaction. (B) The active site is ... change conformation prior to active site interaction (D) The active site is flexible and adjusts to substrate

Last Answer : Answer : B

The hypothesis to explain enzyme– substrate complex formation: (A) Lock and key model (B) Induced fit theory (C) Proenzyme theory (D) Both (A) and (B)

Description : The hypothesis to explain enzyme– substrate complex formation: (A) Lock and key model (B) Induced fit theory (C) Proenzyme theory (D) Both (A) and (B)

Last Answer : Answer : C

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

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

Template/lock and key theory of enzyme action is supported by (A) Enzymes speed up reaction (B) Enzymes occur in living beings and speed up certain reactions (C) Enzymes determine the direction of reaction (D) Compounds similar to substrate inhibit enzyme activity

Description : Template/lock and key theory of enzyme action is supported by (A) Enzymes speed up reaction (B) Enzymes occur in living beings and speed up certain reactions (C) Enzymes determine the direction of reaction (D) Compounds similar to substrate inhibit enzyme activity

Last Answer : Answer : D

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 of the enzyme by binding to a site other than catalytic site (D) Changing the nature of the products formed

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

Last Answer : Answer : C

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 apparent Km (C) Line weaver Bnrk plot is useful for determining Km and Vmax (D) Removal of allosteric inhibitor may result in hyperbolic V-S [s] plot

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

Last Answer : Answer : D

How an enzyme attaches to a substrate using the lock and key hypothesis?

Description : How an enzyme attaches to a substrate using the lock and key hypothesis?

Last Answer : What is the answer ?

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.

In enzyme kinetics Km implies (A) The substrate concentration that gives one half Vmax (B) The dissocation constant for the enzyme substrate comples (C) Concentration of enzyme (D) Half of the substrate concentration required to achieve Vmax

Description : In enzyme kinetics Km implies (A) The substrate concentration that gives one half Vmax (B) The dissocation constant for the enzyme substrate comples (C) Concentration of enzyme (D) Half of the substrate concentration required to achieve Vmax

Last Answer : Answer : A

Key and lock hypothesis of enzyme action was given by (A) Fischer (B) Koshland (C) Buchner (D) Kuhne

Description : Key and lock hypothesis of enzyme action was given by (A) Fischer (B) Koshland (C) Buchner (D) Kuhne

Last Answer : Answer : A

The induced fit model of enzyme action was proposed by (A) Fischer (B) Koshland (C) Mitchell (D) Markert

Description : The induced fit model of enzyme action was proposed by (A) Fischer (B) Koshland (C) Mitchell (D) Markert

Last Answer : Answer : B

‘Lock’ and ‘Key’ theory was proposed by (A) Sorenson (B) Fischer (C) Mehler (D) Sanger

Description : ‘Lock’ and ‘Key’ theory was proposed by (A) Sorenson (B) Fischer (C) Mehler (D) Sanger

Last Answer : Answer : D

Both α-helix and β-pleated sheet conformation of proteins were proposed by (A) Watson and Crick (B) Pauling and Corey (C) Waugh and King (D) Y.S.Rao

Description : Both α-helix and β-pleated sheet conformation of proteins were proposed by (A) Watson and Crick (B) Pauling and Corey (C) Waugh and King (D) Y.S.Rao

Last Answer : Answer : B

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

What is it called when an enzyme is blocked at its active site so the normal substrate can't bind? a. Competitive Inhibition b. Feedback Inhibition c. Noncompetitive Inhibition d. Pathway Modulation

Description : What is it called when an enzyme is blocked at its active site so the normal substrate can't bind? a. Competitive Inhibition b. Feedback Inhibition c. Noncompetitive Inhibition d. Pathway Modulation

Last Answer : a. Competitive Inhibition

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 : 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

Last Answer : Answer : C

In enzyme kinetics Vmax reflects (A) The amount of an active enzyme (B) Substrate concentration (C) Half the substrate concentration (D) Enzyme substrate complex

Description : In enzyme kinetics Vmax reflects (A) The amount of an active enzyme (B) Substrate concentration (C) Half the substrate concentration (D) Enzyme substrate complex

Last Answer : Answer : A

Why do we compare enzymes and substrate to a lock and key?

Description : Why do we compare enzymes and substrate to a lock and key?

Last Answer : What is the answer ?

Lock and Key mechanism of enzyme action? -Biology

Description : Lock and Key mechanism of enzyme action? -Biology

Last Answer : answer:

All of the following statements about thioredoxin reductase are true except: (A) It requires NADH as a coenzyme (B) Its substrates are ADP, GDP, CDP and UDP (C) It is activated by ATP (D) It is inhibited by dADP

Description : All of the following statements about thioredoxin reductase are true except: (A) It requires NADH as a coenzyme (B) Its substrates are ADP, GDP, CDP and UDP (C) It is activated by ATP (D) It is inhibited by dADP

Last Answer : Answer : A

Which one of the following is the correct mathcing of the site of action on the given substrate, the enzyme acting upon it and the end producrt?

Description : Which one of the following is the correct mathcing of the site of action on the given substrate, the enzyme acting upon it and the end producrt?

Last Answer : Which one of the following is the correct mathcing of the site of action on the given substrate, ... ( prop "Amylas")(rarr)` Disaccharie (Maltose)

Which of the following is the correct matchin of the site of action on the given substrate, the enzyme acting state upon it and the end product

Description : Which of the following is the correct matchin of the site of action on the given substrate, the enzyme acting state upon it and the end product

Last Answer : Which of the following is the correct matchin of the site of action on the given substrate, the ... alpha`-amylase `rarr` Disac- charide (Maltose)

Which one of the following is the correct matching of the site of action on the given substrate, the enzyme acting upon it and the end product? (a) Small intestine : Proteins Pepsin  →  Amino acids (b) Stomach : Fats Lipase  →  Micelles (c) Duodenum : Triglycerides Trypsin  →  Monoglycerides (d) Small intestine : Starch α-Amylase  →  Disaccharide (maltose)

Description : Which one of the following is the correct matching of the site of action on the given substrate, the enzyme acting upon it and the end product? (a) Small intestine : Proteins Pepsin  →  ... Trypsin  →  Monoglycerides (d) Small intestine : Starch α-Amylase  →  Disaccharide (maltose)

Last Answer : (d) Small intestine : Starch α-Amylase  →  Disaccharide

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 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

Feedback inhibition of enzyme action is affected by (A) Enzyme (B) Substrate (C) End products (D) None of these

Description : Feedback inhibition of enzyme action is affected by (A) Enzyme (B) Substrate (C) End products (D) None of these

Last Answer : Answer : C

Enzyme involved in joining together two substrates is (A) Glutamine synthetase (B) Aldolase (C) Gunaine deaminase (D) Arginase

Description : Enzyme involved in joining together two substrates is (A) Glutamine synthetase (B) Aldolase (C) Gunaine deaminase (D) Arginase

Last Answer : Answer : A

If curve X in the graph (below) represents no inhibition for the reaction of the enzyme with its substrates, the curve representing the competitive inhibition, of the same reaction is (A) A (B) B (C) C (D) D

Description : If curve X in the graph (below) represents no inhibition for the reaction of the enzyme with its substrates, the curve representing the competitive inhibition, of the same reaction is (A) A (B) B (C) C (D) D

Last Answer : Answer : A

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 : 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

The acquisition energy by glucose fermentation requires A.substrate-level phosphorylation B.electron transport of electrons from NADH C.long-chain fatty acid oxidation D.the enzyme formic-hydrogen lyase

Description : The acquisition energy by glucose fermentation requires A.substrate-level phosphorylation B.electron transport of electrons from NADH C.long-chain fatty acid oxidation D.the enzyme formic-hydrogen lyase

Last Answer : A.substrate-level phosphorylation

Histamine is formed from histidine by the enzyme histidine decarboxylase in the presence of (A) NAD (B) FMN (C) HS-CoA (D) B6-PO4

Description : Histamine is formed from histidine by the enzyme histidine decarboxylase in the presence of (A) NAD (B) FMN (C) HS-CoA (D) B6-PO4

Last Answer : Answer : D

A regulator of the enzyme glucogen synthase is (A) Citric Acid (B) Pyruvate (C) Glucose-6-PO4 (D) GTP

Description : A regulator of the enzyme glucogen synthase is (A) Citric Acid (B) Pyruvate (C) Glucose-6-PO4 (D) GTP

Last Answer : Answer : C

The example of hydrogen transferring Co-enzyme is: (A) B6-PO4 (B) NADP+ (C) TPP (D) ATP

Description : The example of hydrogen transferring Co-enzyme is: (A) B6-PO4 (B) NADP+ (C) TPP (D) ATP

Last Answer : Answer : D

Combination of apoenzyme and coenzyme produces (A) Prosthetic group (B) Holoenzyme (C) Enzyme substrate complex (D) Enzyme product complex

Description : Combination of apoenzyme and coenzyme produces (A) Prosthetic group (B) Holoenzyme (C) Enzyme substrate complex (D) Enzyme product complex

Last Answer : Answer : B

An adult patient with a history of bacterial endocarditis requires prophylactic administration of antibiotics prior to removal of teeth. Indicate the pre-operative regimen:** A. Amoxicillin 2 gram one hour before operation orally B. Penicillin 250 mg orally six hours before operation C. Tetracycline 250-500 mg orally 2 hours before treatment

Description : An adult patient with a history of bacterial endocarditis requires prophylactic administration of antibiotics prior to removal of teeth. Indicate the pre-operative regimen:** A. Amoxicillin 2 gram ... orally six hours before operation C. Tetracycline 250-500 mg orally 2 hours before treatment

Last Answer : A. Amoxicillin 2 gram one hour before operation orally

Characteristic features of active site are (A) Flexible in nature (B) Site of binding (C) Acidic (D) Both (A) and (B)

Description : Characteristic features of active site are (A) Flexible in nature (B) Site of binding (C) Acidic (D) Both (A) and (B)

Last Answer : Answer : D

The active site of an enzyme is formed by (A) R group of amino acids (B) NH2 group of amino acids (C) CO group of amino acids (D) Sulphur bonds which are exposed

Description : The active site of an enzyme is formed by (A) R group of amino acids (B) NH2 group of amino acids (C) CO group of amino acids (D) Sulphur bonds which are exposed

Last Answer : Answer : A

The active site of an enzyme is formed by a few of the enzymes: (A) R groups of the amino acids (B) Amino groups of the amino acids (C) Carboxyl group of the amino acids (D) Exposed sulfur bonds

Description : The active site of an enzyme is formed by a few of the enzymes: (A) R groups of the amino acids (B) Amino groups of the amino acids (C) Carboxyl group of the amino acids (D) Exposed sulfur bonds

Last Answer : Answer : C

Iodo-acetate inhibits enzyme by reacting with which group at the active site of the enzyme?

Description : Iodo-acetate inhibits enzyme by reacting with which group at the active site of the enzyme?

Last Answer : Sulfhydryl group.

Better classroom management means (a) per group work and better interaction among pupils (b) prior preparation of teacher in the making of suitable aids (c) Punctuality of the teachers in coming in the class and finishing the course in time (d) Getting the attention and cooperation of all the students before starting the class/ task (e) Moving around the room to identify pupils having or creating problems (f) Avoid teaching when pupils are not in proper mood (g) All of these

Description : Better classroom management means (a) per group work and better interaction among pupils (b) prior preparation of teacher in the making of suitable aids (c) Punctuality of the teachers in coming in the ... creating problems (f) Avoid teaching when pupils are not in proper mood (g) All of these

Last Answer : (g) All of these

In the manufacture of H3 PO4 (ortho); strong H2 SO4 leaching wet process as compared to electric furnace process (A) Uses lower grade phosphate rock (B) Requires lower capital investment in the plant(C) Produces lower purity acid(D) Is very costly

Description : In the manufacture of H3 PO4 (ortho); strong H2 SO4 leaching wet process as compared to electric furnace process (A) Uses lower grade phosphate rock (B) Requires lower capital investment in the plant (C) Produces lower purity acid (D) Is very costly

Last Answer : (C) Produces lower purity acid

What holds substrates in position during an enzyme catalyzed reaction?

Description : What holds substrates in position during an enzyme catalyzed reaction?

Last Answer : the acive site

Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C(B) Most of the enzyme catalysed reactions involve at least two substrates (C) Enzymes help in increasing the activation energy of the reaction (D) Equilibrium concentrations in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod

Description : Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C ... in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod

Last Answer : (C) Enzymes help in increasing the activation energy of the reaction

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 statement regarding β-oxidation is true? (A) Requires β-ketoacyl CoA as a substrate (B) Forms CoA thioesters (C) Requires GTP for its activity (D) Yields acetyl CoA as a product

Description : Which of the following statement regarding β-oxidation is true? (A) Requires β-ketoacyl CoA as a substrate (B) Forms CoA thioesters (C) Requires GTP for its activity (D) Yields acetyl CoA as a product

Last Answer : Answer : A

Enzymes combine with a ___________at the___________ site to lower the activation energy. a. Substrate; Active b. Product; Noncompetitive c. Product; Active d. Coenzyme; Active

Description : Enzymes combine with a ___________at the___________ site to lower the activation energy. a. Substrate; Active b. Product; Noncompetitive c. Product; Active d. Coenzyme; Active

Last Answer : a. Substrate; Active

The antiviral action of amantadine is exerted through: A. Interaction with the viral M2 protein B. Interaction with a virus directed thymidine kinase C. Inhibition of a viral protease enzyme D. Inhibition of viral RNA mediated DNA synthesi

Description : The antiviral action of amantadine is exerted through: A. Interaction with the viral M2 protein B. Interaction with a virus directed thymidine kinase C. Inhibition of a viral protease enzyme D. Inhibition of viral RNA mediated DNA synthesi

Last Answer : A. Interaction with the viral M2 protein

Substrate concentration at which an enzyme attains half its maximum velocity is (A) Threshold value (B) Michaelis-Menton constant (C) Concentration level (D) None of these

Description : Substrate concentration at which an enzyme attains half its maximum velocity is (A) Threshold value (B) Michaelis-Menton constant (C) Concentration level (D) None of these

Last Answer : Answer : B