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2010-10-27 02:27:59

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  1. Define metabolism.
    is the set of chemical reactions that happen in living organisms to maintain life
  2. Describle how the chemical structure of adenosine triphosphate makes ATP such an ideal and readily available source of energy for cell.

    the high energy bonds btwn the phosphate are weak so they break easily causing a release in energy
  3. what are enzymes?
    proteins that speed up chemical reactions
  4. What is the " activation energy " for the chemical reaction?
    • "barrier" energy that has to be provided to start a chemical reaction.
    • "barrier" has to overcome to start chemical reaction.
  5. Explain how enzymes affect the activation energy of a chemical reaction.
    • - reduce the barrier btwn reactants and products
    • -can occur without activation energy

  6. Definbe substrate.
    specific reactant molecule that binds enzymes
  7. what is the " active site " of an enzyme?
    part of an enzyme where substrates bind and undergo a chemical reaction

  8. explain why only a minute quantity of an enzyme can carry out many chemical reactions.
    • because the enzyme is changing it's shape to fit the substrate each time
    • so they dont have to change enzymes each time
    • - they can keep on reusing the same enzyme
  9. Explain 3 ways how enzymes lower the activation energy of a chemical reaction.
    • 1. correct order ( side by side ) allows chemical reactions to happen quicker
    • 2. creating an environment in which the transition state is stabilized
    • 3. creating an environment with the opposite charge distribution to that of the transition state
  10. Substrate conc. can affect enzyme activity.
    Explain what is meant by the statement " the enzymes are saturated".
    if all the molecules of enzyme in the solution are operating at full capacity (all active sites binding substrate molecules)

  11. explain how temperature affects enzyme activity.
    - too high or too low; enzyme stops working because of denaturation.

  12. explain how pH affects enzyme activity.
    • - above or below optimal causes denaturation
    • pepsin( stomach enzyme) has pH 2

  13. Explain how competitive inhibitors reduce enzyme activity.
    Give an example.
    - it binds to active site, preventing substrate from attching which inhibit or stop enzyme.

    inhibitors: molecules that resenble substrate in structure

    Ex. Use of penicillin in WW1, antibiotic works good on bacteria; it prevents formation of cell wall ( peptidoglycan )

  14. Explain how noncompetitive inhibitors reduce enzyme activity.
    binds to allosteric site and changes the tertiary structure of protein so active site is no longer functional.

  15. Explain how noncompetitive inhibitors are involved in " end product feedback inhibition ".
    • - shutting off all chemical pathways.
    • - end product binds with allosteric site of the 1st enzyme

  16. Define cofactor and coenzyme.
    • Cofactor: non-protein prtion of enzyme ( less specific )
    • ex. organic molecule/contains carbon

    Coenzyme: organic molecule ( more specific) contains a vitamin.