Enzymes

• What are enzymes primarily made of?

  Proteins
• What is the role of the active site in an enzyme?

  The active site binds to a specific substrate
• What term describes the shape of the active site that matches the substrate?

  Complementary shape
• What happens when an enzyme and substrate bind together?

  They form an enzyme-substrate complex
• What is the original model of enzyme action called?

  Lock and key model
• How does the induced fit model differ from the lock and key model?

  The active site changes shape to fit the substrate
• What is the function of enzymes in chemical reactions?

  They act as biological catalysts
• How do enzymes affect activation energy?

  They lower the activation energy required for a reaction
• What is the effect of temperature on enzyme activity?

  Increasing temperature increases the rate of reaction until the optimum temperature
• What happens to enzyme activity after reaching the optimum temperature?

  Enzyme activity decreases as temperature continues to rise
• What causes the decrease in enzyme activity at high temperatures?

  The bonds holding the enzyme's tertiary structure break
• What is denaturation in the context of enzymes?

  Change in the shape of the active site
• How does pH affect enzyme activity?

  Extreme pH levels disrupt ionic bonds in the enzyme
• What is the optimum pH for most body enzymes?

  pH 7
• What happens to enzyme activity as pH moves away from the optimum?

  The rate of reaction decreases
• What is the limiting factor for enzyme concentration when substrate concentration is low?

  Substrate concentration
• What happens when all enzyme active sites are occupied?

  The reaction rate levels off
• What are the factors affecting enzyme action?

  • Temperature
  • pH
  • Enzyme concentration
  • Substrate concentration
• What is the process of enzyme action from substrate binding to product formation?

  1. Substrate binds to the active site
  2. Enzyme-substrate complex forms
  3. Reaction occurs
  4. Product is released
  5. Enzyme is unchanged and can catalyze further reactions
• How do enzyme concentration and substrate concentration graphs differ in explanation?

  • Enzyme concentration: More active sites available increases reaction rate
  • Substrate concentration: More substrate particles available increases reaction rate
• What is the significance of the terms 'complementary' and 'specific' in enzyme action?

  • Complementary: Refers to the shape matching between enzyme and substrate
  • Specific: Refers to the ability of an enzyme to bind to only one substrate
• What is the role of enzymes in metabolic reactions?

  • Catalyze reactions in respiration
  • Facilitate digestion in the small intestine
• What is the energy profile of a reaction with and without an enzyme?

  • Without enzyme: Higher activation energy
  • With enzyme: Lower activation energy
• What happens to the enzyme's active site during denaturation?

  • The active site changes shape
  • It becomes non-complementary to the substrate
• What is the effect of increasing temperature on enzyme activity up to the optimum?

  • Rate of reaction increases due to higher kinetic energy
• What is the effect of extreme pH on enzyme activity?

  • Disrupts ionic bonds in the enzyme's tertiary structure
  • Changes the shape of the active site
• What is enzyme inhibition?

  It is the slowing or prevention of enzyme activity by molecules other than the substrate.
• What is the relationship between enzyme concentration and substrate concentration at saturation point?

  • At saturation, increasing substrate concentration does not increase reaction rate
  • Enzyme concentration becomes the limiting factor
• What are enzyme inhibitors?

  They are molecules that can slow or prevent enzyme activity.
• What are the two types of enzyme inhibitors?

  • Competitive inhibitors
  • Non-competitive inhibitors
• How do competitive inhibitors function?

  They compete with the substrate to bind to the active site of the enzyme.
• What happens when a competitive inhibitor binds to the active site?

  It blocks the active site, preventing the substrate from binding.
• What are non-competitive inhibitors?

  They do not bind to the active site and have a different shape than the substrate.
• Where do non-competitive inhibitors bind?

  They bind to the allosteric site of the enzyme.
• What effect do non-competitive inhibitors have on the active site?

  They cause the active site to change shape, making it non-complementary to the substrate.
• Can the effects of non-competitive inhibitors be permanent?

  Yes, the effects can be permanent or temporary/reversible.
• What happens to the rate of reaction when most enzymes are bound by a non-competitive inhibitor?

  The rate of reaction will stop.
• How can you identify competitive and non-competitive inhibitors on a rate of reaction graph?

  • Competitive inhibitors: Rate increases with substrate concentration and reaches the same endpoint as normal reactions.
  • Non-competitive inhibitors: Rate increases slightly but flatlines early, never reaching the same rate as normal reactions.
• What happens to the rate of reaction with a competitive inhibitor when substrate concentration increases?

  The rate of reaction will still increase and eventually meet the same endpoint as a normal enzyme reaction.
• What is the effect of increasing substrate concentration on a non-competitive inhibitor's rate of reaction?

  It has no effect on the rate of reaction.