Cell Bio

Card Set Information

Cell Bio
2013-03-06 16:04:32

Cell Bio Ch. 3 review from online sources (not book)
Show Answers:

  1. What is ATP made up of?
    3 phosphate grps, 1 ribose & 1 adonine
  2. By what process does the bond in ATP break?
  3. When the terminal phosphate bond is broken, a molecule of inorganic phosphate is formed, and energy is ______
  4. For the reaction of ATP to ADP + inorganic phosphate, the delta g is
  5. Is the reaction from ATP to ADP + inorganic phosphate exergonic or endergonic?
  6. What is energy coupling?
    Use of an exergonic process to drive an endergonic one.
  7. In many cellular reactions, a phosphate group is transferred from ATP to some other molecule in order to make the second molecule less stable. The second molecule is said to be _______
  8. What is a catalyst?
    A chemical agent that speeds up a reaction with out being consumed by the reaction
  9. What effect does an enzyme have on Ea (activation energy)?
    It lowers it
  10. Enzyme
    Protein that acts as a catalyst
  11. Substrate
    Reactant an enzyme acts on
  12. What is meant by induced fit?
    Active site of an enzyme changes slightly so that enzyme binds more snugly to substrate
  13. Explain how protein structure is involved in enzyme specificity
    Unique 3D structure, so it is very specific
  14. Enzymes use a variety of mechanisms to lower activation energy, describe four.
    Act as a template for substrate orientation. Stabilize transition states, stressing substrates. Provide favorable microenvironment. Participate directly in catylic reactions
  15. How does initial concentration of substrate affect enzyme action?
    More substrates, more likely that substrate will find enzyme.
  16. How does pH affect the rate of enzyme action?
    Enzymes work well only on specific ranges of pH
  17. How does temperature affect the rate of enzyme action?
    Increasing temperature makes it so that more substrates collide with enzymes. If it is too high though, the enzyme could denature.
  18. Why can extremes of pH or very high temperatures affect enzyme activity?
    Because they mess up their unique 3D structure by denaturing
  19. Name a human enzyme that functions well in pH 2. Where is it found?
    Pepsin. It is found in the stomach
  20. Distinguish between cofactors and coenzymes. Give examples of each.
    Cofactors are nonprotein helpers for catylic activities. Coenzymes are organic cofactors. Coenzymes are vitamins, cofactors are things like zinc and iron.
  21. Compare and contrast competitive inhibitors and noncompetitive inhibitors.
    They both inhibit the enzyme from doing its job. Competative inhibitors compete with substrates to attach to active site. Noncompetitive inhibitors do not compete and just attach to a different area.
  22. What is allosteric regulation?
    Protein's function at one site is affected by binding of a regulatory molecule on a different site.
  23. How is noncompetitive inhibition similar to allosteric regulation?
    Neither bind directly to the active site. In allosteric though, it does not only work on one subuniti, it works on many.
  24. What is the difference between allosteric activator and an allosteric inhibitor?
    The activator stabilizes the shape with the final active site. The inhibitor stabilizes inactive form of the enzyme
  25. Explain hemoglobin and O2 and cooperativity.
    Hemoglobin has a higher affinity for O2 when there is more O2, so in places like the lungs, it gets more O2, wile in places where there is less, it's affinity for O2 will drop
  26. What is free energy?
    Portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system. G