Enzymes and Catalysis
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Questions and Answers

What percentage of enzymes are proteins?

  • Around 90%
  • Over 50%
  • 99+% (correct)
  • 100%

    • What is the primary role of a catalyst in a chemical reaction?

  • To increase the rate of the reaction without being consumed (correct)
  • To increase the rate of the reaction while being consumed
  • To initiate the reaction and then stop it
  • To decrease the rate of the reaction without being consumed

    • What is the term for the unstable arrangement of atoms during a chemical reaction?

  • Activation energy
  • Ground state
  • Reactant state
  • Transition state (correct)

    • What is the energy required to reach the transition state from the ground state of the reactants?

    <p>Activation energy (B)</p> Signup and view all the answers

    What is the small portion of the enzyme surface where the substrate becomes bound?

    <p>Active site (B)</p> Signup and view all the answers

    What is the model that describes the substrate binding to the enzyme resulting in a change in the conformation of the enzyme?

    <p>Induced fit model (B)</p> Signup and view all the answers

    What is the most likely reason why enzymes exhibit stereospecificity?

    <p>They have a specific shape (C)</p> Signup and view all the answers

    What is the purpose of studying enzyme kinetics?

    <p>To understand the function of enzymes (B)</p> Signup and view all the answers

    What is the term for the reactant in an enzyme-catalyzed reaction?

    <p>Substrate (A)</p> Signup and view all the answers

    What is the benefit of enzymes increasing the rate of chemical reactions?

    <p>They reduce the activation energy (B)</p> Signup and view all the answers

    What is the primary use of understanding enzyme substrate specificity?

    <p>To design inhibitors for specific enzymes (B)</p> Signup and view all the answers

    What does the Lineweaver-Burk plot provide information about?

    <p>Vmax and KM (A)</p> Signup and view all the answers

    What is the unit of Kcat?

    <p>sec^-1 (B)</p> Signup and view all the answers

    What is the effect of extreme pH changes on enzyme function?

    <p>It denatures the enzyme (A)</p> Signup and view all the answers

    What is the usual optimum temperature for enzymes in humans?

    <p>37°C (D)</p> Signup and view all the answers

    What is the result of irreversible inhibition of an enzyme?

    <p>The enzyme is completely nonfunctional (D)</p> Signup and view all the answers

    What is the characteristic of an enzyme with a small KM?

    <p>It requires only a small amount of substrate to become saturated (C)</p> Signup and view all the answers

    What is the purpose of studying the kinetic properties of enzymes?

    <p>To design inhibitors for specific enzymes (D)</p> Signup and view all the answers

    What is the characteristic of an efficient enzyme?

    <p>It has a large Kcat and small KM (C)</p> Signup and view all the answers

    What is the effect of temperature on the rate of an uncatalyzed reaction?

    <p>It increases proportionally with temperature increase (C)</p> Signup and view all the answers

    What is the characteristic of a competitive inhibitor?

    <p>It binds to a different site on the enzyme than the substrate (C)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on the Vmax of an enzyme?

    <p>It decreases the Vmax (A)</p> Signup and view all the answers

    What is the characteristic of a non-competitive inhibitor?

    <p>It binds to both the enzyme and the Enzyme-Substrate complex (C)</p> Signup and view all the answers

    What happens to the Km of an enzyme when a competitive inhibitor is added?

    <p>It increases (A)</p> Signup and view all the answers

    What is the effect of an irreversible inhibitor on an enzyme?

    <p>It inactivates the enzyme (C)</p> Signup and view all the answers

    What is the effect of increasing the substrate concentration on a competitive inhibitor?

    <p>It overcomes the inhibition (B)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on the Km of an enzyme?

    <p>It decreases the Km (B)</p> Signup and view all the answers

    What is the characteristic of an irreversible inhibitor?

    <p>It forms a covalent bond with the enzyme (A)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on the Km of an enzyme?

    <p>It has no effect on the Km (C)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on the Vmax of an enzyme?

    <p>It decreases the Vmax (B)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on the Vmax of an enzyme?

    <p>It decreases the Vmax (A)</p> Signup and view all the answers

    What is the primary use of the Lineweaver-Burk plot?

    <p>To determine Vmax and KM (C)</p> Signup and view all the answers

    What is the effect of an enzyme inhibitor on the enzyme's activity?

    <p>Decreases the enzyme's activity (C)</p> Signup and view all the answers

    What is the significance of a small Km value for an enzyme?

    <p>The enzyme has a high affinity for the substrate (A)</p> Signup and view all the answers

    What is the purpose of studying the kinetic properties of enzymes?

    <p>To design inhibitors for specific enzymes (A)</p> Signup and view all the answers

    What is the effect of temperature on enzyme activity?

    <p>Temperature has an optimal range for enzyme activity (D)</p> Signup and view all the answers

    What is the characteristic of a competitive inhibitor?

    <p>Binds to the active site of the enzyme (B)</p> Signup and view all the answers

    What is the significance of the turnover number (Kcat)?

    <p>Measures the number of substrate molecules reacted per second per enzyme molecule (B)</p> Signup and view all the answers

    What is the effect of pH changes on enzyme function?

    <p>pH changes denature the enzyme (C)</p> Signup and view all the answers

    What is the characteristic of an efficient enzyme?

    <p>Has a high Kcat value and a small Km value (C)</p> Signup and view all the answers

    What is the significance of the Michaelis-Menten equation?

    <p>Describes the steady-state kinetics of enzyme reactions (D)</p> Signup and view all the answers

    What is the main difference between a competitive inhibitor and an uncompetitive inhibitor?

    <p>Competitive inhibitor binds to the active site, while uncompetitive inhibitor binds to the enzyme-substrate complex (B)</p> Signup and view all the answers

    What is the effect of adding more substrate to a reaction inhibited by a non-competitive inhibitor?

    <p>The inhibition remains the same (D)</p> Signup and view all the answers

    What is the characteristic of an irreversible inhibitor?

    <p>It forms a stable covalent bond with the enzyme (A)</p> Signup and view all the answers

    What is the effect of a competitive inhibitor on the Km of an enzyme?

    <p>It increases the Km (A)</p> Signup and view all the answers

    What is the role of Le Chatelier's principle in uncompetitive inhibition?

    <p>It forces the reaction to readjust to the right, simulating the formation of the ES complex (B)</p> Signup and view all the answers

    What is the effect of an irreversible inhibitor on the enzyme acetylcholinesterase (AChE)?

    <p>It inactivates AChE, leading to paralysis and death (A)</p> Signup and view all the answers

    What is the characteristic of a competitive inhibitor that allows it to be overcome by adding more substrate?

    <p>It binds to the active site of the enzyme (B)</p> Signup and view all the answers

    What is the result of the inhibition of an enzyme by a non-competitive inhibitor?

    <p>The Vmax decreases and the Km remains the same (A)</p> Signup and view all the answers

    What is the difference between reversible and irreversible inhibition?

    <p>Reversible inhibition is temporary, while irreversible inhibition is permanent (C)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on the Vmax of an enzyme?

    <p>It decreases the Vmax (A)</p> Signup and view all the answers

    What is the biological function of enzymes?

    <p>To increase the rate of chemical reactions (A)</p> Signup and view all the answers

    What is the primary characteristic of an enzyme-substrate interaction?

    <p>Induced fit (B)</p> Signup and view all the answers

    What is the term for the energy required to reach the transition state?

    <p>Activation energy (A)</p> Signup and view all the answers

    What is the major difference between the lock-and-key model and the induced fit model?

    <p>The conformation of the enzyme (A)</p> Signup and view all the answers

    Why are enzymes important in biological systems?

    <p>They increase the rate of chemical reactions (C)</p> Signup and view all the answers

    What is the purpose of studying enzyme kinetics?

    <p>To understand the rate of chemical reactions (A)</p> Signup and view all the answers

    What is the term for the small portion of the enzyme surface where the substrate binds?

    <p>Active site (D)</p> Signup and view all the answers

    What is the primary advantage of enzymes as catalysts?

    <p>They increase the rate of chemical reactions (D)</p> Signup and view all the answers

    What is the result of enzyme-catalyzed reactions?

    <p>An increase in the rate of chemical reactions (B)</p> Signup and view all the answers

    What is the primary characteristic of a catalyst?

    <p>It increases the rate of a reaction without being consumed (B)</p> Signup and view all the answers

    What is the primary function of a catalyst in a chemical reaction?

    <p>To increase the rate of a chemical reaction without being consumed (D)</p> Signup and view all the answers

    What is the main difference between the lock-and-key model and the induced fit model?

    <p>The change in enzyme conformation upon substrate binding (A)</p> Signup and view all the answers

    What is the energy required to reach the transition state from the ground state of the reactants?

    <p>Activation energy (B)</p> Signup and view all the answers

    What is the characteristic of an enzyme-catalyzed reaction?

    <p>Stereo-specific (B)</p> Signup and view all the answers

    What is the term for the reactant in an enzyme-catalyzed reaction?

    <p>Substrate (D)</p> Signup and view all the answers

    What is the role of the active site in an enzyme-catalyzed reaction?

    <p>To bind the substrate (C)</p> Signup and view all the answers

    What is the benefit of enzymes increasing the rate of chemical reactions?

    <p>To allow reactions to occur under physiological conditions (A)</p> Signup and view all the answers

    What is the characteristic of a reaction that occurs under physiological conditions?

    <p>Optimal pH and temperature (D)</p> Signup and view all the answers

    What is the term for the unstable arrangement of atoms during a chemical reaction?

    <p>Transition state (A)</p> Signup and view all the answers

    What percentage of enzymes are proteins?

    <p>99+% (A)</p> Signup and view all the answers

    What does the size of Km tell us about a particular enzyme?

    <p>That the enzyme requires only a small amount of substrate to become saturated (B)</p> Signup and view all the answers

    What is the purpose of studying enzyme kinetics?

    <p>To understand the various properties of enzymes and their interactions with substrates (D)</p> Signup and view all the answers

    What is the effect of environmental factors on enzyme function?

    <p>Both pH and temperature can affect enzyme function (D)</p> Signup and view all the answers

    What is the characteristic of an enzyme with a high Kcat?

    <p>It is an efficient enzyme with a high turnover number (C)</p> Signup and view all the answers

    What is the difference between reversible and irreversible inhibitors?

    <p>Reversible inhibitors bind non-covalently, while irreversible inhibitors bind covalently (A)</p> Signup and view all the answers

    What is the purpose of the Lineweaver-Burk plot?

    <p>To determine the Km and Vmax of an enzyme from experimental data (A)</p> Signup and view all the answers

    What is the effect of a competitive inhibitor on the Km of an enzyme?

    <p>It increases the Km (B)</p> Signup and view all the answers

    What is the term for the maximum reaction rate reached when the enzyme is completely saturated with substrate?

    <p>Vmax (B)</p> Signup and view all the answers

    Why are enzymes important in drug design?

    <p>They help in designing enzyme inhibitors (A)</p> Signup and view all the answers

    What is the term for the substrate concentration that produces ½ Vmax?

    <p>Km (B)</p> Signup and view all the answers

    What happens to the Km of an enzyme when an uncompetitive inhibitor is added?

    <p>It decreases (A)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on the Enzyme-Substrate complex?

    <p>It decreases the formation of the ES complex (D)</p> Signup and view all the answers

    What is the characteristic of a reversible inhibitor?

    <p>It can be overcome by adding more substrate (D)</p> Signup and view all the answers

    What is the effect of an inhibitor on the Vmax of an enzyme in non-competitive inhibition?

    <p>It decreases the Vmax (C)</p> Signup and view all the answers

    What is the characteristic of an uncompetitive inhibitor?

    <p>It binds to the ES complex only (D)</p> Signup and view all the answers

    What is the result of irreversible inhibition of an enzyme?

    <p>The enzyme is inactivated permanently (A)</p> Signup and view all the answers

    What is the effect of increasing the substrate concentration on a non-competitive inhibitor?

    <p>It has no effect on the inhibition (B)</p> Signup and view all the answers

    What is the characteristic of a competitive inhibitor?

    <p>It binds to the active site of the enzyme (D)</p> Signup and view all the answers

    What is the primary role of a catalyst in a chemical reaction?

    <p>To increase the rate of the reaction without being consumed (C)</p> Signup and view all the answers

    What is the effect of Le Chatelier's principle on the Km of an enzyme in uncompetitive inhibition?

    <p>It decreases the Km (A)</p> Signup and view all the answers

    What is the characteristic of enzymes that allows them to function in physiological conditions?

    <p>Stereospecificity (B)</p> Signup and view all the answers

    What is the difference between a competitive inhibitor and an uncompetitive inhibitor?

    <p>Competitive inhibitors bind to the active site, while uncompetitive inhibitors bind to the ES complex (B)</p> Signup and view all the answers

    What is the term for the energy required to reach the transition state from the ground state of the reactants?

    <p>Activation energy (A)</p> Signup and view all the answers

    What is the most likely model of enzyme-substrate interaction?

    <p>Induced fit model (C)</p> Signup and view all the answers

    What is the percentage of enzymes that are proteins?

    <p>99+% (A)</p> Signup and view all the answers

    What is the term for the unstable arrangement of atoms during a chemical reaction?

    <p>Transition state (B)</p> Signup and view all the answers

    What is the benefit of enzymes increasing the rate of chemical reactions?

    <p>To allow the reaction to occur at a faster rate (C)</p> Signup and view all the answers

    What is the characteristic of enzymes that allows them to exhibit catalytic activity?

    <p>Specific binding to substrates (A)</p> Signup and view all the answers

    What is the term for the reactant in an enzyme-catalyzed reaction?

    <p>Substrate (A)</p> Signup and view all the answers

    What is the characteristic of an efficient enzyme?

    <p>High turnover rate (B)</p> Signup and view all the answers

    What does the size of Km indicate about an enzyme?

    <p>The enzyme's affinity for the substrate (C)</p> Signup and view all the answers

    What is the unit of Kcat?

    <p>sec-1 (A)</p> Signup and view all the answers

    How does the environment surrounding an enzyme affect its function?

    <p>It can directly affect enzyme function (B)</p> Signup and view all the answers

    What is the purpose of a Lineweaver-Burk plot?

    <p>To determine the Km and Vmax of an enzyme (A)</p> Signup and view all the answers

    What is the effect of extreme pH changes on enzyme function?

    <p>It denatures the enzyme, destroying its catalytic ability (C)</p> Signup and view all the answers

    What is the characteristic of an efficient enzyme?

    <p>Low Km and high Kcat (D)</p> Signup and view all the answers

    What is the effect of temperature on the rate of an uncatalyzed reaction?

    <p>It increases the rate of the reaction proportionally (C)</p> Signup and view all the answers

    What is the significance of the Michaelis-Menten equation?

    <p>It assumes steady-state kinetics (A)</p> Signup and view all the answers

    What is the effect of an irreversible inhibitor on an enzyme?

    <p>It forms a covalent bond with the enzyme, inactivating it (C)</p> Signup and view all the answers

    What is the primary use of understanding enzyme substrate specificity?

    <p>To design inhibitors for specific enzymes (C)</p> Signup and view all the answers

    What is the primary function of an enzyme in a chemical reaction?

    <p>To increase the rate of reaction (C)</p> Signup and view all the answers

    What is the term for the energy required to reach the transition state from the ground state of the reactants?

    <p>Activation energy (C)</p> Signup and view all the answers

    What is the most likely model of enzyme-substrate interaction?

    <p>Induced fit model (C)</p> Signup and view all the answers

    What is the primary benefit of enzymes increasing the rate of chemical reactions?

    <p>To increase the reaction rate (B)</p> Signup and view all the answers

    What is the characteristic of enzymes that allows them to increase the rate of chemical reactions?

    <p>Catalytic activity (B)</p> Signup and view all the answers

    Why is it important to study enzyme kinetics?

    <p>To understand the function of enzymes in chemical reactions (D)</p> Signup and view all the answers

    What is the primary function of the active site of an enzyme?

    <p>To bind the substrate (A)</p> Signup and view all the answers

    What is the term for the arrangement of atoms in the process of being formed or broken during a chemical reaction?

    <p>Transition state (C)</p> Signup and view all the answers

    What is the primary reason why enzymes are stereospecific?

    <p>To minimize the distance to the transition state (C)</p> Signup and view all the answers

    What is the primary characteristic of a catalyst in a chemical reaction?

    <p>It is not consumed during the reaction (C)</p> Signup and view all the answers

    What is the primary use of understanding enzyme substrate specificity?

    <p>To design inhibitors for specific enzymes (C)</p> Signup and view all the answers

    What is the significance of the Lineweaver-Burk plot?

    <p>It gives information about the enzyme's affinity for the substrate (B)</p> Signup and view all the answers

    What is the effect of a reversible inhibitor on the enzyme's Vmax?

    <p>It does not affect the Vmax (C)</p> Signup and view all the answers

    What is the characteristic of an enzyme with a high catalytic efficiency?

    <p>It has a high Kcat value and a low Km value (B)</p> Signup and view all the answers

    What is the effect of environmental changes on enzyme function?

    <p>It can denature the enzyme, destroying its catalytic ability (D)</p> Signup and view all the answers

    What is the purpose of studying enzyme kinetics?

    <p>To understand the mechanism of enzyme action (B)</p> Signup and view all the answers

    What is the difference between a reversible and an irreversible inhibitor?

    <p>A reversible inhibitor binds non-covalently, while an irreversible inhibitor binds covalently (B)</p> Signup and view all the answers

    What is the significance of the Michaelis-Menten equation?

    <p>It is used to describe the kinetics of enzyme-catalyzed reactions (B)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on the enzyme's Km?

    <p>It does not affect the Km value (C)</p> Signup and view all the answers

    What is the characteristic of an enzyme with a high Kcat value?

    <p>It is efficient in converting substrate to product (D)</p> Signup and view all the answers

    In competitive inhibition, what happens to Vmax?

    <p>Remains unchanged (B)</p> Signup and view all the answers

    What is the characteristic of an uncompetitive inhibitor?

    <p>Binds to the enzyme-substrate complex (C)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on Km?

    <p>Remains unchanged (D)</p> Signup and view all the answers

    What is the characteristic of an irreversible inhibitor?

    <p>Forms a covalent bond with the enzyme (B)</p> Signup and view all the answers

    What is the effect of adding more substrate to a reaction inhibited by a competitive inhibitor?

    <p>Can completely overcome the inhibition (C)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on Vmax?

    <p>Decreases (A)</p> Signup and view all the answers

    What is the characteristic of a non-competitive inhibitor?

    <p>Binds to the enzyme and the enzyme-substrate complex (A)</p> Signup and view all the answers

    What is the effect of a competitive inhibitor on Km?

    <p>Increases (B)</p> Signup and view all the answers

    What is the characteristic of an irreversible inhibition?

    <p>Irreversible (D)</p> Signup and view all the answers

    What is the difference between competitive and uncompetitive inhibition?

    <p>Competitive inhibitors bind to the active site, uncompetitive inhibitors bind to the enzyme-substrate complex (C)</p> Signup and view all the answers

    What is the effect of a competitive inhibitor on Vmax?

    <p>It remains unchanged (D)</p> Signup and view all the answers

    Which type of inhibition occurs when the inhibitor binds to the enzyme-substrate complex?

    <p>Uncompetitive inhibition (B)</p> Signup and view all the answers

    What is the effect of a non-competitive inhibitor on the binding of substrate to the enzyme?

    <p>It has no effect on the binding (B)</p> Signup and view all the answers

    What is the difference between reversible and irreversible inhibition?

    <p>Reversible inhibition is temporary, while irreversible inhibition is permanent (C)</p> Signup and view all the answers

    What is the characteristic of an irreversible inhibitor?

    <p>It forms a stable covalent bond with the enzyme (D)</p> Signup and view all the answers

    What is the effect of a competitive inhibitor on Km?

    <p>It increases (C)</p> Signup and view all the answers

    What is the effect of an uncompetitive inhibitor on Vmax and Km?

    <p>Vmax decreases, Km decreases (C)</p> Signup and view all the answers

    What is the characteristic of a competitive inhibitor?

    <p>It binds to the active site of the enzyme (D)</p> Signup and view all the answers

    What is the effect of an irreversible inhibitor on the enzyme?

    <p>It permanently inactivates the enzyme (A)</p> Signup and view all the answers

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