Enzymes

• what are enzymes ?

  a protein in the tertiary structure which catalayse reactions by lowering activation energy
• why can enzymes only attach to substrates that are complementary in shape ?

  • the active site is specific and unique in shape due to the specific folding and bonding in the tertiary structure of the protein
  • the location of the bonds is determined by the primary structure.
• what is the induced fit model ?

  • the enzyme active site is induced, or slightly changes shape , to fit the substrate
• how does temperature affect enzyme activity ?

  • temp to low, not enough kinetic energy for successful collisions between the enzyme and substrate
  • temp to high, enzymes denature, active site looses shape, enzyme substrate complex can't form
• how does ph affect enzyme activity ?

  either too high or to low ph will

  • interfere with the charges in the amino acids
  • this will break the bonds holding the tertiary structure together
  • therfore leading to the active site changing shape
• how does substrate and enzyme collision affect enzymes ?

  • Reaction rate will be slowed down if there is insufficient substrates
  • if there is insufficient enzymes than the active sites will be saturated with substrate and unable to work any quicker
• what is a competitive inhibitor ?

  • a molecule that is the same shape and the substrate
  • so can bind to the active site
  • and prevent enzyme-substrate complexes
  • if you add lots of substrate it can knock the inhibitors out of the active site
• what is a non-competitive inhibitor ?

  • binds to the allosteric site
  • causes the active site to change shape
  • so no enzyme-substrate complexes can form at all