Enzymes

• What happens when enzyme or substrate concentration increases?

  More enzyme-substrate complexes form
• Why does the reaction rate plateau when substrate concentration is too high?

  All enzyme active sites become occupied
• What occurs when enzyme concentration increases but substrate is limited?

  Rate doesn't increase much due to limited substrate
• Where do non-competitive inhibitors bind?

  To an allosteric site on the enzyme
• How do non-competitive inhibitors affect enzyme activity?

  They alter the enzyme’s tertiary structure
• Can increasing substrate concentration overcome non-competitive inhibition?

  No, it does not increase the rate of reaction
• Where do competitive inhibitors bind?

  To the active site of the enzyme
• How do competitive inhibitors affect enzyme activity?

  They block the substrate from binding
• Can increasing substrate concentration overcome competitive inhibition?

  Yes, it increases the chance of binding
• How do enzymes speed up reactions?

  By lowering the activation energy required
• What is the 'lock and key' model?

  Enzyme's active site fits exactly with substrate
• What is the 'induced fit' model?

  Enzyme changes shape to fit substrate closely
• What factors affect enzyme activity?

  Temperature, pH, enzyme concentration, substrate concentration, inhibitors
• What happens to enzymes at high temperatures?

  They denature and change shape of active site
• Why does enzyme activity decrease at low temperatures?

  Particles move slower, fewer successful collisions
• What does it mean if an enzyme is 'denatured'?

  Its structure is permanently altered and nonfunctional
• What is an enzyme-substrate complex?

  Temporary structure formed when enzyme binds substrate
• Why do enzymes only work on specific substrates?

  Active site shape is complementary to one substrate