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 described as (A) Independent of enzyme concentration (B) A constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration

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 described as (A) Independent of enzyme concentration (B) A constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration
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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

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

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

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

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

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

Last Answer : Answer : A

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

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

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

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

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

Km value of enzyme is substrate concentration at (A) ½ Vmax (B) 2 Vmax (C) ½ Vmax (D) 4 Vmax

Description : Km value of enzyme is substrate concentration at (A) ½ Vmax (B) 2 Vmax (C) ½ Vmax (D) 4 Vmax

Last Answer : Answer : D

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 rate of a chemical reaction may be independent of substrate concentration (D) States that the reaction rate is proportional to substrate concentration

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

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 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

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

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

Arrhenius equation K = Ae-E a / R T In some reactions, Rate of reaction is directly proportional to. Concentration of catalyst Catalyst used in Bio-Chemical reactions is called. Enzymes Reactions catalyzed by light are called as. Photo catalyzed or Photosensitised reactions

Description : Arrhenius equation K = Ae-E a / R T In some reactions, Rate of reaction is directly proportional to. Concentration of catalyst Catalyst used in Bio-Chemical reactions is called. Enzymes Reactions catalyzed by light are called as. Photo catalyzed or Photosensitised reactions

Last Answer : Define order of reaction

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

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

In non-competitive enzyme action (A) Vmax is increased (B) Apparent km is increased (C) Apparent km is decreased (D) Concentration of active enzyme molecule is reduced

Description : In non-competitive enzyme action (A) Vmax is increased (B) Apparent km is increased (C) Apparent km is decreased (D) Concentration of active enzyme molecule is reduced

Last Answer : Answer : C

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

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

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

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

The reaction catalysed by phosphofructokinase (A) Is activated by high concentrations of ATP and citrate (B) Uses fruitose-1-phosphate as substrate (C) Is the rate-limiting reaction of the glycolytic pathway (D) Is inhibited by fructose 2, 6-bisphosphate

Description : The reaction catalysed by phosphofructokinase (A) Is activated by high concentrations of ATP and citrate (B) Uses fruitose-1-phosphate as substrate (C) Is the rate-limiting reaction of the glycolytic pathway (D) Is inhibited by fructose 2, 6-bisphosphate

Last Answer : C

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

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

Last Answer : Answer : B

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

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

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

In competitive enzyme activity inhibition (A) Apparent Km is decreased (B) Apparent Km is increased (C) Vmax is increased (D) Vmax is decreased

Description : In competitive enzyme activity inhibition (A) Apparent Km is decreased (B) Apparent Km is increased (C) Vmax is increased (D) Vmax 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

What determines the rate of an enzyme-catalyzed reaction, and why is it important?

Description : What determines the rate of an enzyme-catalyzed reaction, and why is it important?

Last Answer : The important factors that influence the rate of an enzymic reaction are the concentration of the enzyme itself, the substrate concentration(s), and factors such as pH, temperature, presence of ... predict how the enzyme functions, and thus to suggest ways of affecting it with antimetabolites.  

In enzyme assays, all the following are kept constant except (A) Substrate concentration (B) Enzyme concentration (C) pH (D) Temperature

Description : In enzyme assays, all the following are kept constant except (A) Substrate concentration (B) Enzyme concentration (C) pH (D) Temperature

Last Answer : Answer : B

Oxidative phosphorylation involves (A) Electron transport system (B) Substrate level phosphorylation (C) Reaction catalyzed by succinic thiokinase in TCA cycle (D) None of the above

Description : Oxidative phosphorylation involves (A) Electron transport system (B) Substrate level phosphorylation (C) Reaction catalyzed by succinic thiokinase in TCA cycle (D) None of the above

Last Answer : (A) Electron transport system

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

Description : 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

Last Answer : Answer : B

The presence of a non competitive inhibitor (A) Leads to both an increase in the Vmax of a reaction and an increase in Km (B) Leads to a decrease in the observed Vmax (C) Leads to a decrease in Km and Vmax (D) Leads to an increase in Km without affecting Vmax

Description : The presence of a non competitive inhibitor (A) Leads to both an increase in the Vmax of a reaction and an increase in Km (B) Leads to a decrease in the observed Vmax (C) Leads to a decrease in Km and Vmax (D) Leads to an increase in Km without affecting Vmax

Last Answer : Answer : B

The order of reaction is the number of moles whose concentrations determine the rate of a reaction at a given temperature Give the integrated equation for first order reaction. K = (2.303 / t) * log (a / a-x) Rate equation of first order reaction is. dx/dt = K * (a-x) where ‘a’ is the initial concentration of reactants ‘x’ is the amount reacted in time t seconds

Description : The order of reaction is the number of moles whose concentrations determine the rate of a reaction at a given temperature Give the integrated equation for first order reaction. K = (2.303 / t) * log (a ... a' is the initial concentration of reactants x' is the amount reacted in time t seconds

Last Answer : What is Threshold energy ?

The free energy change, AG (A) Is directly proportional to the standard free energy change, AG (B) Is equal to zero at equilibrium (C) Can only be calculated when the reactants and products are present at 1mol/1 concentrations (D) Is equal to –RT in keq

Description : The free energy change, AG (A) Is directly proportional to the standard free energy change, AG (B) Is equal to zero at equilibrium (C) Can only be calculated when the reactants and products are present at 1mol/1 concentrations (D) Is equal to –RT in keq

Last Answer : B

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

Identify the INCORRECT statement below regarding chemical equilibrium. A All chemical reactions are, in principle, reversible. B Equilibrium is achieved when the forward reaction rate equals the reverse reaction rate. C Equilibrium is achieved when the concentrations of species become constant. D Equilibrium is achieved when the reaction quotient, Q, equals the equilibrium constant. E Equilibrium is achieved when reactant and product concentrations are equal.

Description : Identify the INCORRECT statement below regarding chemical equilibrium. A All chemical reactions are, in principle, reversible. B Equilibrium is achieved when the forward reaction rate equals the ... equilibrium constant. E Equilibrium is achieved when reactant and product concentrations are equal.

Last Answer : E Equilibrium is achieved when reactant and product concentrations are equal.

Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually __________ the concentration of catalyst, if it doesnot entail a chain mechanism.(A) Proportional to(B) Independent of(C) Inversely proportional to(D) Proportional to the square o

Description : Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually __________ the concentration of ... to (B) Independent of (C) Inversely proportional to (D) Proportional to the square o

Last Answer : (A) Proportional to

At very high concentration of enzymes, the rate of fermentation chemical reaction is __________ the concentration of reactants. (A) Independent of (B) Directly proportional to (C) Inversely proportional to (D) Proportional to the square of

Description : At very high concentration of enzymes, the rate of fermentation chemical reaction is __________ the concentration of reactants. (A) Independent of (B) Directly proportional to (C) Inversely proportional to (D) Proportional to the square of

Last Answer : (A) Independent of

. A first order irreversible reaction, A → B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors. (A) Both conversion as well as concentration are same (B) Conversion in both will be the same but concentrations will be different (C) Both the conversion as well as concentrations will be different (D) None of these

Description : . A first order irreversible reaction, A → B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two ... be different (C) Both the conversion as well as concentrations will be different (D) None of these

Last Answer : (B) Conversion in both will be the same but concentrations will be different

What is the order of chemical reaction as shown in the bellow figure, if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quadrupled when the concentrations of both B & C were doubled? (A) 1 (B) 2 (C) 3 (D) 4

Description : What is the order of chemical reaction as shown in the bellow figure, if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B ... the concentrations of both B & C were doubled? (A) 1 (B) 2 (C) 3 (D) 4

Last Answer : (B) 2

Enzymes activity is controlled by (A) pH of the solution (B) Temperature (C) Concentration of the enzyme (D) Concentration of the substrate (E) All of these

Description : Enzymes activity is controlled by (A) pH of the solution (B) Temperature (C) Concentration of the enzyme (D) Concentration of the substrate (E) All of these

Last Answer : Answer : C

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

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

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

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

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

For the reaction `a+brArrc+d`, initially concentrations of a and b are equal and at equilibrium the concentration of a . What will be the equilibrium

Description : For the reaction `a+brArrc+d`, initially concentrations of a and b are equal and at equilibrium the concentration of a . What will be the equilibrium

Last Answer : For the reaction `a+brArrc+d`, initially concentrations of a and b are equal and at equilibrium the concentration of a ... ? A. 2 B. 9 C. 4 D. 3

Which one of the following statements is not correct? A Since voltage depends on concentrations, using standard conditions makes it easier to compare different electrochemical reactions. B We have to measure the cell potential to obtain the difference in potential energy because the potential of half-reactions cannot be measured directly. C The direction of a redox reaction can only be determined experimentally. D Half-cell potentials for half-reactions are determined by combining the relevant half-cell with a standardised half-cell.

Description : Which one of the following statements is not correct? A Since voltage depends on concentrations, using standard conditions makes it easier to compare different electrochemical reactions. B We have ... half-reactions are determined by combining the relevant half-cell with a standardised half-cell.

Last Answer : C The direction of a redox reaction can only be determined experimentally. 

25. In a reaction, A + B  Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be written as: (1) Rate = k[A]2 [B] (2) Rate = k[A] [B]2 (3) Rate = k[A]2 [B]2 (4) Rate = k[A] [B]

Description : 25. In a reaction, A + B  Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be ... Rate = k[A] [B]2 (3) Rate = k[A]2 [B]2 (4) Rate = k[A] [B]

Last Answer : Rate = k[A]2 [B] (

The following abnormality in PRPP synthetase can cause primary gout: (A) High Vmax (B) Low Km (C) Resistance to allosteric inihbition. (D) All of these

Description : The following abnormality in PRPP synthetase can cause primary gout: (A) High Vmax (B) Low Km (C) Resistance to allosteric inihbition. (D) All of these

Last Answer : Answer : D

In competitive inhibition which of the following kinetic effect is true ? (A) Decreases both Km and Vmax (B) Increases both Km and Vmax (C) Decreases Km without affecting Vmax (D) Increases Km without affecting Vmax

Description : In competitive inhibition which of the following kinetic effect is true ? (A) Decreases both Km and Vmax (B) Increases both Km and Vmax (C) Decreases Km without affecting Vmax (D) Increases Km without affecting Vmax

Last Answer : Answer : D

Competitive inhibitors (A) Decrease the Km (B) Decrease the Vmax (C) Increase the Km (D) Increase the Vmax

Description : Competitive inhibitors (A) Decrease the Km (B) Decrease the Vmax (C) Increase the Km (D) Increase the Vmax

Last Answer : Answer : C

In Lineweaver-Burk plot, the y-intercept represents (A) Vmax (B) Km (C) Km (D) 1/Km

Description : In Lineweaver-Burk plot, the y-intercept represents (A) Vmax (B) Km (C) Km (D) 1/Km

Last Answer : Answer : B

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

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