Enzymes

• What are enzymes made of?

  Globular proteins
• What is the function of an enzyme?

  to catalyse a chemical reaction by lowering the activation energy
• What does the induced fit hypothesis suggest?

  When the enzyme binds to the substrate to form an enzyme substrate complex, the active site alters shape to be complimentary to the substrate
• What is the active sites shape determined by?

  The enzymes tertiary structure
• Why are enzymes specific?

  A gene codes for the order of amino acids. This determines the primary structure of the enzyme.
• What are the factors affecting enzyme activity?

  temperature , ph , substrate concentration
• Why do enzymes denature at high temperatures?

  - high temperature = high kinetic energy

  - causes vibrations that break hydrogen bonds

  - tertiary structure changes

  - active site is no longer complimentary to substrate

  - fewer enzyme substrate complex can be made

  - fewer products
• Explain enzyme activity at low temperatures

  - low temperature = low kinetic energy

  - fewer successful collisions

  - fewer enzyme substrate complex

  - fewer products
• What does a high PH mean?

  substance is alkaline, high concentration of OH- ions
• What does a low PH mean?

  substance is acidic, high concentration of H+ ions
• How is enzyme activity affected above and below optimum PH?

  - ions can alter ionic bonds and hydrogen bonds

  - tertiary structure changes

  - active site is no longer complimentary to substrate

  - fewer enzyme substrate complex

  - fewer products
• How does a substrate concentration of 0 affect enzyme activity?

  - no enzyme substrate complex can form

  - no products
• What is a competitive inhibitor?

  molecules that have a similar shape to the substrate therefore bind to the active site and block it
• What is a non competitive inhibitor?

  binds to the enzyme away from its active site which alters the tertiary structure therefore changing the shape of the active site
• How can you reduce the effects of inhibitors?

  increasing substrate concentration