Enzymes

• What are enzymes?


  Biological catalysts
• Explain the induced fit model of enzyme action.

  • Shape of active site is nit directly complementary to the substrate and is slightly flexible.
  • Conformational change enables ES complexes to form.
  • This puts strain on substrate bonds, lowering the activation energy.
• How have models of enzymes action changed?

  From the lock and key to the induced fit model.
• Name 5 factors that affect the rate of enzyme controlled reactions.

  • Enzyme concentration
  • substrate concentration
  • Temperature
  • pH
  • concentration of inhibators
• How does substrate concentration affect rate of reaction?

  Rate increases proportionally to substrate conc. Rate levels off when the max number of es complexes form.
• How does enzyme conc affect the rate of reaction?

  It increases then plateaus when max number of es complexes are formed.
• How does temp affect ror?

  Rate increases as kinetic energy increases and peaks at an optimum temp. Above the optimum, ionic and hydrogen bonds break, the enzyme denatures and is no longe complementary to the substrate.
• How does pH affect ror?

  Enzymes have a narrow optimum pH range. Outside the range, the enzyme denatures.
• What are the differences between competitive and non-competitive inhibitors?

  Competitive inhibitors compete with the substrate for the active site of an enzyme, while non-competitive inhibitors bind to a different site on the enzyme and change its shape.
• What is the formula for pH?

  pH = -log[H+]