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Allosteric Effectors quiz

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  • What is an allosteric effector?
    An allosteric effector is a regulatory molecule that binds to an allosteric site on an enzyme to regulate its activity.
  • What is the difference between heterotrophic and homotrophic allosteric effectors?
    Heterotrophic effectors affect the enzyme's activity on a different molecule, while homotrophic effectors use the substrate itself as the effector.
  • What does the prefix 'hetero' indicate in heterotrophic effectors?
    'Hetero' means different, indicating the effector is a different molecule from the substrate.
  • What does the prefix 'homo' indicate in homotrophic effectors?
    'Homo' means the same, indicating the substrate itself acts as the effector.
  • How do allosteric activators affect the R state of an enzyme?
    Allosteric activators stabilize the R state, increasing its concentration.
  • How do allosteric inhibitors affect the T state of an enzyme?
    Allosteric inhibitors stabilize the T state, increasing its concentration.
  • What effect do allosteric activators have on the allosteric constant (L naught)?
    Activators decrease L naught by increasing the concentration of the R state.
  • What effect do allosteric inhibitors have on the allosteric constant (L naught)?
    Inhibitors increase L naught by increasing the concentration of the T state.
  • How do allosteric activators affect the sigmoidal curve of enzyme kinetics?
    Activators shift the sigmoidal curve to the left, indicating increased enzyme activity at lower substrate concentrations.
  • How do allosteric inhibitors affect the sigmoidal curve of enzyme kinetics?
    Inhibitors shift the sigmoidal curve to the right, indicating decreased enzyme activity at the same substrate concentrations.
  • In the example of ATCase, which molecule acts as an allosteric activator?
    ATP acts as an allosteric activator for ATCase.
  • In the example of ATCase, which molecule acts as an allosteric inhibitor?
    CTP acts as an allosteric inhibitor for ATCase.
  • How do activators and inhibitors affect the initial reaction velocity (v naught)?
    Activators increase the initial reaction velocity, while inhibitors decrease it.
  • Do allosteric effectors always affect the Vmax of an enzyme?
    No, not all effectors affect Vmax, but some can; activators can increase Vmax and inhibitors can decrease it.
  • What is the main function of allosteric effectors in enzyme regulation?
    Allosteric effectors regulate enzyme activity by binding to sites other than the active site, altering the enzyme's conformation and activity.