Enzymology Lesson 5
21 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the effect of substrate concentration on the rate of reaction until maximum velocity is reached?

  • The rate initially increases, then decreases as substrate saturation occurs.
  • The rate increases as substrate concentration decreases.
  • The rate increases as substrate concentration increases. (correct)
  • The rate remains constant regardless of substrate concentration.

    • Which factor does NOT affect the reaction rate of enzymes?

  • Light intensity (correct)
  • Substrate concentration
  • Temperature
  • Enzyme concentration

    • What is the role of an allosteric inhibitor?

  • To facilitate reversible covalent modification
  • To decrease the enzyme's catalytic activity (correct)
  • To bind to the active site of the enzyme
  • To increase the enzyme's catalytic activity

    • What is the term for the maximum rate of a reaction when the enzyme is fully saturated with substrate?

    <p>Maximum velocity (Vmax) (C)</p> Signup and view all the answers

    What describes an enzyme that has a significant effect on the overall rate of a metabolic pathway?

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

    Which modification is most commonly associated with reversible covalent modification of enzymes?

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

    How does the concentration of enzyme affect reaction velocity?

    <p>Increasing enzyme concentration increases reaction velocity until substrate saturation occurs. (B)</p> Signup and view all the answers

    What is the apoenzyme?

    <p>The protein portion of the enzyme (D)</p> Signup and view all the answers

    Which of the following is an example of an allosteric modulator?

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

    Which statement is true regarding the relationship between product concentration and substrate concentration in enzymatic reactions?

    <p>Product concentration increases as substrate concentration declines. (C)</p> Signup and view all the answers

    What is the impact of pH on enzymatic activity?

    <p>Each enzyme has a specific pH range for optimal activity. (B)</p> Signup and view all the answers

    Which term describes a molecule that is covalently bound to a protein and is essential for enzyme activity?

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

    What characterizes a metabolic pathway?

    <p>A sequence of several enzymatic reactions where the product of one becomes the substrate for the next. (A)</p> Signup and view all the answers

    What is the primary role of an enzyme in a biological reaction?

    <p>To catalyze a specific chemical reaction. (C)</p> Signup and view all the answers

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

    <p>It binds the substrate and catalyzes its transformation. (B)</p> Signup and view all the answers

    Why do enzymes have high substrate specificity?

    <p>They can only bind to one specific substrate. (C)</p> Signup and view all the answers

    How do enzymes affect the activation energy needed for a reaction?

    <p>They lower the activation energy, facilitating the reaction. (D)</p> Signup and view all the answers

    What happens when an enzyme's active site is modified?

    <p>The enzyme's activity can be modulated. (D)</p> Signup and view all the answers

    What is formed when an enzyme binds to its substrate?

    <p>An enzyme-substrate (E-S) complex. (D)</p> Signup and view all the answers

    Which of the following describes the stages of an enzymatic reaction?

    <p>E-S complex → Transition complex → E-P complex → Separation. (B)</p> Signup and view all the answers

    What characterizes the catalytic activity of enzymes regarding reaction conditions?

    <p>They are compatible with mild conditions of life. (D)</p> Signup and view all the answers

    Flashcards

    Allosteric enzyme

    A regulatory enzyme whose activity is modulated by noncovalent binding of metabolites at a site other than the active site.

    Allosteric site

    The specific location on an allosteric enzyme where modulator molecules bind to regulate its activity.

    Covalent modification

    Modification of enzyme activity through the covalent alteration of amino acid residues, often involving phosphorylation.

    Coenzyme

    A complex organic or metalloorganic molecule that assists enzymes in catalyzing reactions, often derived from vitamins.

    Signup and view all the flashcards

    Apoenzyme

    The protein portion of an enzyme that is inactive without its cofactor or coenzyme.

    Signup and view all the flashcards

    Enzymatic Kinetics

    The study of reaction rates and their changes due to experimental conditions.

    Signup and view all the flashcards

    V0 (Rate of Reaction)

    The number of substrate molecules converted to product per unit time.

    Signup and view all the flashcards

    Substrate Concentration

    The amount of substrate available for the enzyme to convert into product.

    Signup and view all the flashcards

    Maximum Velocity (Vmax)

    The highest rate of reaction when enzyme saturation occurs.

    Signup and view all the flashcards

    Optimal pH

    The specific pH level at which an enzyme operates best.

    Signup and view all the flashcards

    Metabolic Pathway

    A sequence of enzymatic reactions where products serve as substrates for the next reactions.

    Signup and view all the flashcards

    Regulatory Enzyme

    An enzyme that controls the rate of a metabolic pathway through activation or inhibition.

    Signup and view all the flashcards

    External Factors

    Conditions such as enzyme and substrate concentrations, pH, and temperature affecting reaction rates.

    Signup and view all the flashcards

    Active Site

    The part of an enzyme that binds the substrate and catalyzes a reaction.

    Signup and view all the flashcards

    Substrate Specificity

    Enzymes can bind only one specific substrate for a reaction.

    Signup and view all the flashcards

    Enzymatic Efficiency

    Enzymes increase the reaction rate under mild conditions.

    Signup and view all the flashcards

    Activation Energy

    The energy needed to start a chemical reaction.

    Signup and view all the flashcards

    Transition State

    A high-energy state that occurs during the conversion of substrate to product.

    Signup and view all the flashcards

    E-S Complex

    The complex formed when an enzyme binds to its substrate.

    Signup and view all the flashcards

    E-P Complex

    The complex formed after the enzyme transforms the substrate into product.

    Signup and view all the flashcards

    Study Notes

    Enzymology - Lesson 5

    • Enzymes are proteins that catalyze specific chemical reactions.
    • Enzymes increase the rate of biological reactions.
    • Water-soluble vitamins function as coenzymes.
    • Enzyme activity is regulated.

    Enzyme Structure

    • Active site: The region on an enzyme's surface that binds to the substrate and catalyzes its transformation.
    • The active site's catalytic activity depends on the integrity of the enzyme's native protein conformation.
    • Amino acid residues in the active site bind the substrate and catalyze the transformation.
    • Enzymes increase the reaction speed.

    Enzyme Properties

    • High specificity: Enzymes bind only to specific substrates and catalyze only one type of reaction.
    • Efficiency: Enzymes increase the reaction rate significantly.
    • Enzymatic reactions occur in specific pockets called active sites.
    • Enzyme activity can be regulated.

    How Enzymes Work

    • Enzymes lower the activation energy needed for a reaction to occur.
    • Transition state: A high-energy intermediate state during a reaction.
    • Enzymes stabilize the transition state, decreasing the activation energy.
    • Enzymes form an enzyme-substrate complex, accelerating reactions.

    Enzymatic Reactions

    • Enzyme binds to its substrate.
    • Enzyme-substrate complex forms.
    • Transition state forms.
    • E-P complex forms.
    • Enzyme releases the product.
    • Enzymes increase reaction rates.

    Enzymatic Kinetics

    • Study of reaction rates and their changes due to experimental parameters.
    • V0: Initial velocity of a reaction.
    • Rate or velocity of a reaction (V): number of substrate molecules converted to product per unit time.
    • Product concentration will increase as substrate concentration declines.

    External Factors Affecting Reaction Rate

    • Enzyme concentration: Affects the reaction rate.
    • Substrate Concentration: Affects the reaction rate until maximum velocity is reached.
    • pH: Influences each enzyme's activity.
    • Temperature: Affects enzyme activity.

    Metabolic Pathway

    • Sequences of consecutive enzymatic reactions.
    • Product of one reaction becomes the substrate in the next.
    • Each pathway includes multiple enzymes.
    • Regulatory enzymes control the reaction rate within a pathway.

    Regulators of Enzyme Activity - Allosteric Regulation

    • An allosteric enzyme: A regulatory enzyme whose catalytic activity is modulated by non-covalent binding of a specific metabolite at a site other than the active site.
    • Allosteric inhibitor: A modulator that slows down or stops the enzyme's activity.
    • Allosteric activator: A modulator that enhances the enzyme's activity.

    Regulators of Enzyme Activity - Reversible Covalent Modification

    • Enzyme activity is modulated by covalent modification of its amino acid residues including phosphorylation/dephosphorylation.
    • Common in hormonal signal responses (e.g., adrenaline, glucagon, insulin).
    • Phosphorylation is a widespread covalent modification mechanism.

    Regulators of Enzyme Activity - Phosphorylation Cascade

    • Series of proteins in a pathway that get phosphorylated.
    • Receptor activates protein kinase 1.
    • Activated protein kinase 1 activates protein kinase 2.
    • Activated protein kinase 2 activates the target protein, triggering a cellular response.

    Coenzymes

    • Apoenzyme: The protein portion of an enzyme.
    • Prosthetic group: A metal ion or organic compound covalently bound to the apoenzyme.
    • Cofactor: Inorganic ions.
    • Coenzyme: Complex organic or metalloorganic molecules.
    • Vitamins are a source of coenzymes.
    • Non-vitamin coenzymes exist.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Enzymology Lesson 5 PDF

    Description

    This quiz covers key concepts in enzymology, focusing on enzyme structure, properties, and mechanisms. Understand how enzymes catalyze reactions and the importance of the active site in their function. Test your knowledge on enzyme specificity and regulation.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser