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Lock and Key Vs. Induced Fit Models quiz #1

1 학생이 이 점이 도움이 되었다고 느꼈습니다
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  • What is the main difference between the lock and key model and the induced fit model of enzyme-substrate interaction?
    The lock and key model proposes that the enzyme's active site is rigid and perfectly complementary to the substrate, while the induced fit model suggests that the active site is flexible and adjusts its shape to better fit the transition state, allowing conformational changes in both the enzyme and substrate.
  • Why is the induced fit model considered a more accurate representation of enzyme catalysis compared to the lock and key model?
    The induced fit model is considered more accurate because it prioritizes stabilizing the transition state rather than the enzyme-substrate complex, which lowers the activation energy and speeds up the reaction, unlike the lock and key model that may not decrease or could even increase the activation energy.
  • How does stabilization of the enzyme-substrate complex affect the activation energy in the lock and key model?
    In the lock and key model, excessive stabilization of the enzyme-substrate complex can result in the activation energy remaining the same or even increasing, which is undesirable because enzymes are expected to lower the activation energy to catalyze reactions efficiently.
  • What is the main structural difference between the lock and key model and the induced fit model of enzyme-substrate interaction?
    The lock and key model has a rigid, perfectly complementary active site, while the induced fit model features a flexible active site that adjusts to fit the transition state.
  • In the lock and key model, how does the enzyme's active site interact with the substrate?
    The enzyme's active site is rigid and perfectly matches the substrate, allowing the substrate to fit like a puzzle piece without any conformational changes.
  • Why can the lock and key model result in no decrease or even an increase in activation energy?
    Because the enzyme-substrate complex is overly stabilized, the activation energy may remain the same or increase, which is not desirable for catalysis.
  • How does the induced fit model explain the lowering of activation energy in enzyme-catalyzed reactions?
    The induced fit model prioritizes stabilizing the transition state rather than the enzyme-substrate complex, which lowers the activation energy and speeds up the reaction.
  • What conformational changes occur in the induced fit model during enzyme-substrate binding?
    Both the enzyme's active site and the substrate undergo conformational changes to better fit the transition state.
  • Why is the induced fit model considered a more accurate representation of enzyme catalysis than the lock and key model?
    It more effectively decreases the activation energy by stabilizing the transition state, which is the desired effect of enzyme catalysis.
  • What is the effect of stabilizing the enzyme-substrate complex in the lock and key model on the reaction rate?
    Stabilizing the enzyme-substrate complex can prevent the activation energy from decreasing, thus not increasing the reaction rate as expected for enzyme catalysis.
  • How does an enzyme recognize its substrate according to the lock and key and induced fit models?
    In the lock and key model, the enzyme recognizes its substrate through a rigid active site that is perfectly complementary in shape to the substrate, allowing a precise fit. In the induced fit model, the enzyme's active site is flexible and adjusts its shape to better fit the substrate and especially the transition state, allowing for conformational changes in both the enzyme and substrate.
  • What is meant by the induced fit of an enzyme?
    The induced fit of an enzyme refers to the process where the enzyme's active site is flexible and changes shape upon substrate binding, becoming more complementary to the transition state than to the substrate itself. This conformational change in both the enzyme and substrate helps stabilize the transition state and lowers the activation energy of the reaction.
  • What makes an enzyme substrate specific according to the lock and key and induced fit models?
    Enzyme substrate specificity arises from the complementarity between the enzyme's active site and the substrate. In the lock and key model, specificity is due to the rigid, perfectly shaped active site that matches the substrate. In the induced fit model, specificity results from the enzyme's ability to undergo conformational changes that allow the active site to adapt to and bind the substrate, especially stabilizing the transition state.