Enzymes and Catalysis Quiz
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Questions and Answers

What initiates enzyme catalysis in the process described?

  • The substrate entering the active site (correct)
  • The enzyme changing shape
  • The formation of product
  • The breaking of bonds
  • What is the role of the induced-fit mechanism in enzyme activity?

  • It breaks the substrate's bonds
  • It synthesizes new molecules
  • It changes the enzyme's shape for better binding (correct)
  • It allows the substrate to be released
  • Which reaction is an example of a decomposition reaction as described?

  • Galactose and glucose to lactose
  • Lactose to glucose and galactose (correct)
  • Glycogen to glucose
  • Glucose to glycogen
  • In the synthesis reaction described, what are the products formed?

    <p>Glycogen from glucose</p> Signup and view all the answers

    What happens to the enzyme after the products are released?

    <p>The enzyme remains unchanged and can catalyze another reaction</p> Signup and view all the answers

    What binds to the enzyme during the reaction process?

    <p>Substrate</p> Signup and view all the answers

    During the enzyme-catalyzed reactions, what occurs when the enzyme changes shape?

    <p>New bonds are formed between substrates</p> Signup and view all the answers

    Which enzyme is specifically involved in the digestion of lactose?

    <p>Lactase</p> Signup and view all the answers

    What distinguishes catalyzed reactions from uncatalyzed reactions?

    <p>Catalyzed reactions occur faster due to the presence of enzymes.</p> Signup and view all the answers

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

    <p>It permits only a single substrate to bind.</p> Signup and view all the answers

    In the context of enzyme activity, what is meant by 'enzyme-substrate complex'?

    <p>A temporary association formed when a substrate binds to an enzyme.</p> Signup and view all the answers

    Which statement about enzymes is accurate?

    <p>Most enzymes are globular proteins with a unique three-dimensional structure.</p> Signup and view all the answers

    What effect do enzymes typically have on activation energy?

    <p>Enzymes decrease the activation energy required for reactions.</p> Signup and view all the answers

    What characterizes exergonic reactions?

    <p>Reactants have more energy within their chemical bonds than products.</p> Signup and view all the answers

    Which statement is true about endergonic reactions?

    <p>Reactants contain less energy than the products.</p> Signup and view all the answers

    During which type of reaction is energy typically released?

    <p>Decomposition reactions.</p> Signup and view all the answers

    How does the potential energy change in endergonic reactions?

    <p>Potential energy increases net throughout the reaction.</p> Signup and view all the answers

    If a reaction requires energy to proceed, what type of reaction is it likely to be?

    <p>Endergonic reaction.</p> Signup and view all the answers

    Which process is classified as an exergonic reaction?

    <p>Cellular respiration.</p> Signup and view all the answers

    What occurs to the energy released during an exergonic reaction as products are formed?

    <p>It is lost as heat to the environment.</p> Signup and view all the answers

    Which of the following statements describes the energy flow in exergonic and endergonic reactions?

    <p>Endergonic reactions absorb energy while exergonic reactions don't.</p> Signup and view all the answers

    What are the two main components of a chemical equation?

    <p>Reactants and products</p> Signup and view all the answers

    In a balanced chemical equation, what condition must be met?

    <p>Same number of each type of element on both sides</p> Signup and view all the answers

    What is a decomposition reaction?

    <p>A reaction where a large molecule is broken down into smaller ones</p> Signup and view all the answers

    Which term refers to the collective term for all chemical reactions occurring in the body?

    <p>Metabolism</p> Signup and view all the answers

    What characterizes a catabolic reaction?

    <p>It is a breakdown reaction involving the release of energy</p> Signup and view all the answers

    What is the role of the arrow in a chemical equation?

    <p>It indicates the direction of the reaction</p> Signup and view all the answers

    What distinguishes an anabolic reaction from a catabolic reaction?

    <p>Anabolic reactions utilize energy while catabolic reactions release energy</p> Signup and view all the answers

    How can chemical reactions be classified based on changes in chemical energy?

    <p>They can be classified as either endothermic or exothermic reactions</p> Signup and view all the answers

    What is the primary reason why heat is usually not available to do work?

    <p>Heat represents kinetic energy associated with random motion.</p> Signup and view all the answers

    What does the first law of thermodynamics state?

    <p>Energy can neither be created nor destroyed; it can only change in form.</p> Signup and view all the answers

    When energy is transformed, what happens to some of the energy according to the second law of thermodynamics?

    <p>Some energy is lost as heat.</p> Signup and view all the answers

    Which of the following best describes metabolism?

    <p>The collection of chemical reactions occurring in the body.</p> Signup and view all the answers

    Which example illustrates the conversion of energy as stated in the first law of thermodynamics?

    <p>Chemical energy in food converting to electrical energy in brain cells.</p> Signup and view all the answers

    What often occurs in the human body as energy is converted from one form to another?

    <p>Energy is lost in the form of heat.</p> Signup and view all the answers

    In the context of thermodynamics, which scenario best exemplifies the second law?

    <p>A car using fuel converts chemical energy to mechanical energy, causing heat loss.</p> Signup and view all the answers

    How does the body's maintenance of homeostasis relate to energy conversion?

    <p>It utilizes energy transformations to produce heat necessary to sustain biological functions.</p> Signup and view all the answers

    What is the primary substrate used in the process described?

    <p>Glucose</p> Signup and view all the answers

    What is a likely consequence of severe increases in temperature on enzyme activity?

    <p>Protein denaturation</p> Signup and view all the answers

    At what temperature range do human enzymes typically function best?

    <p>95-104°F</p> Signup and view all the answers

    What happens to enzyme flexibility as temperature decreases?

    <p>It becomes more rigid</p> Signup and view all the answers

    What could be a result of moderate fever on enzyme activity?

    <p>Increased efficiency</p> Signup and view all the answers

    Which statement is true regarding the relationship between enzyme temperature and reaction rate?

    <p>Optimal temperature maximizes enzyme activity until denaturation occurs.</p> Signup and view all the answers

    What is released as a product of the action of glycogen synthase?

    <p>Glycogen</p> Signup and view all the answers

    What are weak intramolecular interactions responsible for in enzyme function?

    <p>Stabilizing the active site</p> Signup and view all the answers

    Study Notes

    Energy, Chemical Reactions, and Cellular Respiration

    • Living organisms need energy for various functions, including powering muscles, pumping blood, absorbing nutrients, exchanging gases, synthesizing molecules, and establishing cellular ion concentrations.
    • Glucose is broken down through metabolic pathways to form ATP, the cell's energy currency.

    Energy: States of Energy

    • Energy is the capacity to do work. It exists in two fundamental states:
      • Potential energy: Stored energy, related to position.
      • Kinetic energy: Energy of motion.
    • Energy is convertible between potential and kinetic forms. (E.g., water at the top of a dam possesses potential energy; its movement downstream has kinetic energy.)
    • A concentration gradient across a plasma membrane stores potential energy. Sodium ions concentrated outside a cell hold potential energy. Their movement into the cell releases that energy.

    Potential Energy and the Plasma Membrane

    • Sodium ion concentration gradient across the plasma membrane of a cell.
    • The sodium ions outside the cell have potential energy. (analogous to water at the top of a dam)
    • The movement of sodium ions from high concentration outside the cell to a lower concentration inside the cell releases kinetic energy.
    • This movement can be harnessed to do cellular work.

    Energy: Forms of Energy

    • Chemical Energy (A Form of Potential Energy):

      • Stored in a molecule's chemical bonds.
      • Crucial for cellular processes (movement, synthesis, gradients).
      • Released during bond breaking.
      • Triglycerides are for long-term energy storage in adipose tissue.
      • Glycogen is stored in liver and muscle.
      • ATP is stored and used immediately in all cells.
      • Protein can be a fuel source, but it has more critical functions.
    • Kinetic Energy Forms:

      • Electric energy: Movement of charged particles (e.g., nerve impulses, ion movement across membranes).
      • Mechanical energy: Energy of motion in objects/structures (e.g., muscle contraction).
      • Sound energy: Compression and vibration of molecules, (e.g., eardrum vibration).
      • Radiant energy: Energy of electromagnetic waves (e.g., visible light for vision, UV radiation). Higher frequency light carries more energy. This energy can damage DNA.
      • Heat: Kinetic energy of random molecular motion. Typically unusable for work in biological systems.

    Energy: Laws of Thermodynamics

    • First Law: Energy cannot be created or destroyed, only changed in form.
    • Second Law: When energy changes forms, some energy is lost as heat; usable energy decreases, with every transformation.

    Chemical Reactions: Chemical Equations

    • Metabolism: Collective term for all chemical reactions in the body.
    • Chemical reactions: Occur when chemical bonds in molecules break and new bonds form. These changes are summarized in chemical equations.

    Chemical Reactions: Classification of Chemical Reactions

    • Classification Based on Changes in Chemical Structure:
      • Catabolism: Breakdown of complex molecules to simpler ones.
      • Anabolism: Building complex molecules from simpler ones.
    • Classification Based on Changes in Chemical Energy:
      • Exergonic reactions: Release more energy than they require; decomposition reactions.
      • Endergonic reactions: Absorb more energy than they release; synthesis reactions.
    • ATP cycling: Continuous formation and breakdown of ATP, the cell's primary energy currency.

    Enzymes

    • Function: Biological catalysts that accelerate chemical reactions by lowering activation energy without being consumed in the reaction.
    • Mechanism of action: Substrate binds to the enzyme's active site, forming an enzyme-substrate complex. Induced-fit: shape change in the active site stresses existing chemical bonds, allowing new bonds to form. Products are released and the enzyme is ready for another reaction.

    Enzymes: Structure and Location

    • Enzymes are largely globular proteins.
    • The active site is a specific region in the enzyme, allowing only a target substrate shape to bind. This site permits a highly controlled chemical reaction.

    Enzymes: Temperature

    • Optimal temperature for enzymes that function in the human body is moderate (95-104°F), slightly above the average body temperature.
    • Higher temperatures can denature proteins, which alters the enzyme's critical shape.

    Enzymes: pH

    • Enzymes function best in a narrow pH range.
    • Changes in pH can denature proteins, affecting the functioning of the enzyme.
    • Optimal pH might vary depending on location within the body (e.g., stomach).

    Clinical View: Lactose Intolerance

    • Caused by a deficiency in the enzyme lactase, which is needed to break down the disaccharide lactose into simpler sugars (glucose and galactose).
    • Symptoms often include abdominal upset.
    • Treatment involves avoiding milk or using lactase enzymes to digest lactose.

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    A&P Ch. 3 PPT Quinn (2) PDF

    Description

    Test your knowledge on enzyme catalysis and the mechanisms involved. This quiz covers key concepts like the induced-fit mechanism, reaction types, and the fate of enzymes after product release. Challenge yourself and deepen your understanding of enzymatic reactions.

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