enzymes

• what is the activation energy? 


  energy required to bring about a reaction
• what is the active site?

  a group of amino acids that makes up the region of an enzyme into which the substrate fits to catalyse a reaction
• what is a competitive inhibitor?

  a form of inhibitor which binds to active site of the enzyme preventing the binding of substrate
• whats an enzyme-substrate complex?

  the intermediate formed when a substrate molecule interacts with the active site of an enzyme
• what is the induced fit model?

  a mechanism of interaction between an enzyme and a substrate, the substrate fits into the active site of an enzyme, changes shape to allow an enzyme-substrate complex to be formed
• what is an inhibitor?

  a substance which reduces the activity of an enzyme
• what is the lock and key model?

  an analogy of how enzymes work, only the correctly sized substrate fits into the active site of the enzyme
• what is metabolism? 


  all the chemical processes that take place in living organisms
• what is a non-competitive inhibitor?

  a form of inhibitor which does not bind to the active site of the enzyme which prevents the binding of substrate
• what is a substrate?

  a substance that is acted or used by another substance or process, fits into the active site of an enzyme
• what are the 4 factors affecting enzyme action?

  • enzyme concentration
  • substrate concentration
  • temperature
  • pH
• what does increasing the enzyme concentration do?

  increases the number of active sites available for substrates to collide with, more ES-complexes can form, the rate of reaction then increases until there are no more substrates to bind to
• what does increasing the substrate concentration do?

  increases the rate of reaction as kore substrate molecules, more collisions so more ES-complexes form, rate of reaction will slow when all active sites are occupied
• what does increasing the temp do?

  more kinetic energy, more collisions, more ES-complexes form.

  each has an optimum temp once reached if the temp increases more the enzymes denature and rate of reaction decreases
• what does increasing the pH do?

  enzymes have an optimum pH most work at 7, above and below the pH the enzymes become denatured so no more ES-complexes are formed
• what do competitive inhibitors do?

  compete with the substrate to bind to the active site of enzyme
• what do the competitive inhibitor block?

  the active site so substrates cannot bind
• what do non-competitive inhibitors do?

  bind to a site away from the active site causing the active site to change shape so its no longer complimentary