1.4.2 Enzymes

• How do enzymes lower the activation energy?

  They stablize the transition state of the reaction by holding molecules in close proximity
• What do enzymes and substrates bind together to make?

  Enzyme substrate complex
• What's the difference between the induced fit and lock and key model how how an enzyme works?

  In the lock and key model the enzyme and substrate are fully complimentary. In the induced fit model the active site adjusts to the substrate
• What is a competative inhibitor?

  The inhibitor is a similar shape to the substrate and binds to the active site.
• What's a non-competative inhibitor?

  The inhibitor is a different shape to the substrate and binds to a region that is not the active site, causing a change in the shape of the active site.
• Which inhibitor is effected by more substrates and why?

  The competative as there's a higher change the substrate will bind to the enzyme before the inhibitor
• Some proteases are secreted as extracellular enzymes by bacteria, suggest one advantage to a bacterium of doing this in their natural environment.

  This can allow the bacterium to digest proteins so that they can absorb amino acids for growth.
• Some mammals have membrane bound dipeptidases, describe the importance and action of these membrane bound dipeptidases.

  These dipeptides hydrolyse these proteins to release amino acids. These amino acids can then cross the cell membrane.
• A new antibiotic targets bacterial ATP synthase but does not affect human ATP synthase, suggest why.

  Human ATP synthase has a different shape active site to bacterial ATP synthase.