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2013-11-06 14:41:39
Vet Med

Module 2 - Week 1 - Enzymes
Show Answers:

  1. Do enzymes change the equilibrium of a reaction?
    No - they increase the rate of the forward and reverse reactions
  2. During an enzyme catalysed reaction what kind of complex is formed?
    An enzyme-substrate complex
  3. Where is the enzyme carbonic anhydrase found?
    Found in the cytoplasm of RBCs - it fixes CO2 for transport through the body
  4. What are the requirements for enzyme activity?
    • Optimum pH
    • Optimum temperature
    • Coenzymes
    • Enzyme cofactors
  5. Where are coenzymes derived from?
    Vitamins - this is why we must have vitamins in our diet
  6. What do enzyme cofactors do?
    They help in the bonding of a substrate in an active site.  Cofactors are usually metal ions e.g. Ca2+, Fe2+, Cu2+, Mn2+
  7. What type of curve do normal enzyme reactions display?
    A hyperbolic curve
  8. Explain the kinetics of a normal enzyme reaction
    At a constant concentration of enzyme, the reaction rate increases with increasing substrate concentration until a maximum rate is reached (and the graph levels off).  AT this Vmax there is a saturation effect- all the enzyme sites are filled with substrate (so adding more substrate has no effect on rate).
  9. What is the Km of an enzyme reaction?
    The substrate concentration at which half the total number of binding sites are in use
  10. Which type of inhibition, competitive or non-competitive, can be overcome with the addition of more substrate?  Why?
    Competitive inhibition can be overcome by the addition of more substrate; because both the substrate and the inhibitor are competing for the active site adding more substrate means there is more chance of substrate binding with the active site instead of inhibitor.
  11. What type of curve do allosteric enzymes display?
    Sigmoidal curves