A sigmoidal plot of substrate concentration ([S]) verses reaction velocity (V) may indicate (A) Michaelis-Menten kinetics (B) Co-operative binding (C) Competitive inhibition (D) Non-competitive inhibition

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Answer :

Answer :  B

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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

Last Answer : Answer : C

Description : From the L ineweaver-Burk p lot of Michaelis-Menten equation, Km and Vmax can be determined when V is the reaction velocity at substrate concentration S, the X-axis experimental data are expressed as (A) 1/V (B) V (C) 1/S (D) S

Last Answer : Answer : C

Description : Kinetics of an allosteric enzyme are explained by (A) Michaelis-Menten equation (B) Lineweaver-Burk plot (C) Hill plot (D) All of these

Last Answer : Answer : C

Description : Michaelis – Menten equation is used to explain the effect of substrate concentration on (A) Carbohydrate (B) Enzyme (C) Lipid (D) Protein

Last Answer : Answer : B

Description : ........................ studied the kinetics of enzyme catalysis. a. Arrhenius b. Rutherford c. Micheal Faraday d. Michaelis & Menten

Last Answer : d. Michaelis & Menten

Description : The Michaehis-Menten hypothesis: (A) Postulates the formation of an enzyme substrate complex (B) Enables us to calculate the isoelectric point of an enzyme (C) States that the ... independent of substrate concentration (D) States that the reaction rate is proportional to substrate concentration

Last Answer : Answer : A

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

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

Description : The Michaelis constant, Km is (A) Numerically equal to ½ Vmax (B) Dependent on the enzyme concentration (C) Independent of pH (D) Numerically equal to the substrate concentration that gives half maximal velocity

Last Answer : Answer : D

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

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

Description : What is Michaelis-Menten Theory ?

Last Answer : It is otherwise called enzyme-substrate complex theory. The enzyme combines with the substrate, to form an enzyme-substrate complex, which immediately breaks down to the enzyme and the product.

Description : Enzyme inhibition caused by a substance resembling substrate molecule is (A) Competitive inhibition (B) Non-competitive inhibition (C) Feedback inhibition (D) Allosteric inhibition

Last Answer : Answer : A

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

Description : What is Michaelis Menten constant? -Biology

Last Answer : answer:

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

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

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

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

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 : 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

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))

Description : In reversible non-competitive enzyme activity inhibition (A) Vmax is increased (B) Km is increased (C) Km is decreased (D) Concentration of active enzyme is reduced

Last Answer : Answer : D

Description : When [s] is equal to Km, which of the following conditions exist? (A) Half the enzyme molecules are bound to substrate (B) The velocity of the reaction is equal to Vmax (C) The velocity of the reaction is independent of substrate concentration (D) Enzyme is completely saturated with substrate

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Description : The phenomenon of inhibition of glycolysis by O2 is termed as (A) Red drop (B) Pasteur effect (C) Michaelis effect (D) Fischer’s effect

Last Answer : Answer : B

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

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

Description : Lineweaver – Burk double reciprocal plot is related to (A) Substrate concentration (B) Enzyme activity (C) Temperature (D) Both (A) and (B) ENZYMES 145

Last Answer : Answer : D

Description : The rate of an enzyme catalyzed reaction was measured using several substrate concentrations that were much lower than Km, the dependence of reaction velocity on substrate concentration can best be ... constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration

Last Answer : Answer : C

Description : If the substrate concentration is much below the km of the enzyme, the velocity of the reaction is (A) Directly proportional to substrate concentration (B) Not affected by enzyme concentration (C) Nearly equal to Vmax (D) Inversely proportional to substrate concentration

Last Answer : Answer : A

Description : When the velocity of an enzymatic reaction equals Vmax, substrate concentration is (A) Half of Km (B) Equal to Km (C) Twice the Km (D) Far above the Km

Last Answer : Answer : D

Description : In competitive inhibition of enzyme action (A) The apparent Km is decreased (B) The apparent Km is increased (C) Vmax is decreased (D) Apparent concentration of enzyme molecules decreased

Last Answer : Answer : B

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

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

Last Answer : Answer : A

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

Last Answer : Answer : A

Description : The inhibition of succinate dehydrogenase by malonate by (A) Competitive inhibition (B) Non-competitive inhibition (C) Uncompetitive inhibition (D) Feedback inhibition

Last Answer : Answer : A

Description : Allosteric enzymes regulate the formation of products by (A) Feedback inhibition (B) Non-competitive inhibition (C) Competitive inhibition (D) Repression-derepression

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Description : Allosteric inhibition is also known as (A) Competitive inhibition (B) Non-competitive inhibition (C) Feedback inhibition (D) None of these

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

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Description : Give examples of non-competitive inhibition.

Last Answer : Di-isopropyl fluoro phosphate inhibits trypsin, fluoride inhibits and enolase.

Description : What are the salient features of non-competitive inhibition? 

Last Answer : Non-competitive inhibitor has no structural similarity with the substrate. 2. It is generally not reversible 3. Km is not changed. 4. Vmax is reduced.

Description : Velocity maximum for an enzyme at half the substrate concentration gives (A) The molecular weight of the enzyme (B) Km value (C) Isoelectric pH (D) Pk value

Last Answer : Answer : B

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 : Feedback inhibition of enzyme is influenced by (A) Enzyme (B) External factors (C) End product (D) Substrate

Last Answer : Answer : C

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

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Description : After operative removal of the parathyroid glands resulting into hypoparathyroidism the concentration of the serum calcium may drop below (A) 11 mg (B) 10 mg (C) 9 mg (D) 7 mg

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Description : Tetracycline hydrochloride conditioning of root surfaces in periodontal surgery is to: A. Sterilise the root surface B. May enhance binding of fibronectin and fibroblast C. Aids in re-mineralising the root surface D. Assist the biding of lamina dura E. Prevents post operative infections

Last Answer : B. May enhance binding of fibronectin and fibroblast

Description : Feedback term refers to (A) Effect of substrate on rate of enzymatic reaction (B) Effect of end product on rate reaction (C) Effect of enzyme concentration on rate of reaction (D) Effect of external compound on rate of reaction

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Description : Sigmoidal oxygen dissociation curve is a property of (A) Haemoglobin (B) Carboxyhaemoglobin (C) Myoglobin (D) Methaemoglobin

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