Enzymes

• What is the structure of enzymes classified as?


  Tertiary structure proteins
• What is the function of enzymes?


  To catalyze different reactions
• What part of the enzyme is involved in catalyzing reactions?


  The active site
• What is the relationship between the active site and the substrate?


  The active site is complementary in shape to the substrate
• What term describes the complex formed when an enzyme binds to its substrate?


  Enzyme-substrate complex
• How does the tertiary structure of a protein relate to enzyme function?


  The tertiary structure determines the shape of the active site
• What determines the unique shape of an enzyme's active site?


  The sequence of amino acids in the primary structure
• What happens to the substrate when it binds to the active site?


  The substrate slightly distorts in shape
• What is the effect of enzymes on activation energy?


  Enzymes lower the activation energy required for reactions
• What are the two models that explain how enzymes catalyze reactions?


  Lock and key model, induced fit model
• How does the lock and key model describe enzyme action?


  The enzyme's active site is an exact fixed shape like a lock
• What does the induced fit model suggest about the enzyme's active site?


  The active site slightly changes shape to mold around the substrate
• What happens to the bonds in the substrate when it binds to the enzyme in the induced fit model?


  The bonds in the substrate are weakened by strain
• What occurs after the products are formed in an enzyme-catalyzed reaction?


  The active site returns to its original shape
• What is the accepted model for how enzymes function?


  The induced fit model
• What are the key features of the lock and key model of enzyme action?


  • Enzyme's active site is a fixed shape
  • Substrate must be exactly complementary to fit
  • Random collisions lead to enzyme-substrate complex formation
• What are the key features of the induced fit model of enzyme action?


  • Active site is almost complementary to the substrate
  • Active site changes shape to mold around the substrate
  • Strain on substrate bonds lowers activation energy