gibbs energy

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gibbs energy
2013-02-20 14:51:46

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  1. Synthesis or degradation of biomolecules involves?
    change in energy
  2. Thermodynamics is the study of?
    energy stages
  3. Thermodynamics predicts is a reaction wil occur?
    spontaneous (it will process without energy imput)
  4. Free energy change (delta G) does what?
    determines direction of the reaction
  5. If delta G<0, then
    the reaction proceeds
  6. delta S=?
    entropy change (state of disorder)
  7. delta H=?
    enthalpy change ( heat energy change from making and breaking bonds)
  8. delta G at standard conditions?
    • -delta G measures at 25degrees C
    • -all reactants & products at 1M
    • -EXCEPT H+ which is at pH at 7, 10^-7
  9. 1st law of thermodynamics?
    • energy is neither created nor destroyed
    • -but it can be changed from one form to another ( chemical, electrical, heat, work)
  10. If we HYDROLYZE one mole of ATP to ADP & Pi, then?
    the products have 32kJ less chemical energy than the reactants
  11. q=?
  12. w=?
  13. so 32kJ of energy released by hydrolysis of 1 mole of ATP is released as ?
    heat or used to do "work"
  14. "Work" can be?
    • -motion
    • -formation of concentration gradients
    • -chemical work
  15. 2nd law of thermodynamics
    the entropy of the universe INCREASES
  16. Entropy is what?
    a measure of disorder or randomness
  17. Increasing entropy means?
  18. Cells can decrease their entropy how?
    ONLY if the surroundings INCREASE their entropy by a greater extent
  19. Diffusion in response to concentration gradients is?
  20. Gibbs Free Energy:

    Spontaneous Reaction
    • -free energy decreases, delta G negative
    • -energy is released by the reaction
    • -reaction is said to be exergonic
  21. Gibbs Free Energy:

    Non-Spontaneous Reaction:
    • -free energy increases, delta G is positive
    • -energy is absorbed by the reaction
    • -reaction is said to be endergonic
  22. An example of an EXERGONIC REACTION is:
    ATP + H20 ---- ADP + Pi       -32 released
  23. An example of an ENDERGONIC reaction is:
    glucose 6-phosophate to fructose 6 phosphate +1.7
  24. At equilibrium, G=?
  25. When the system is NOT at equilibrium:
    -Actual delta G will be DIFFERENT than delta G prime

    -Delta G depends on CONCENTRATIONS OF REACTANTS AND PRODUCTS (delta prime does not)

    - Farther the reaction is FROM equilibrium, the MORE NEGATIVE delta G will be!!!!
  26. Frequently in biochemistry 2 reactions are ___ or occur simultaenously.
  27. if delta G>0 ?
    endergonic reaction
  28. if delta G <0
    exergonic reaction
  29. In a coupled reaction what happens?
    the sum of the reactions is EXERGONIC (the exergonic reaction drives the endergonic reaction)
  30. In a coupled reaction, both reactions (exergonic and endergonic) must what?
    must occur on the SAME ENZYME
  31. A very EXERGONIC REACTION can be coupled to ?
    ATP formation
  32. Phosphate transfer potential:
    Compounds with more NEGATIVE delta G hydrolysis can transfer phosphate to compound with more POSITIVE.
  33. What can transfer Pi to ADP to make ATP?
    • -PEP
    • -1, 3 BPG
    • -phosphocreatine
    • -phosphoArg
  34. What cant transfer Pi to ADP to make ATP?
    • - Glucose 1-P
    • - Glucose 6P
    • -glycerol 3-P
  35. Phosphate transfer potential:

    High energy compounds:
    • -phosophoenolpyruvate
    • -phosphocreatine
  36. Phosphate transfer potential:

    Low energy compounds?
  37. Hydrolysis of ATP provides the free energy to drive most?
    ENDERGONIC reactions
  38. What is the primary currency of cells?
  39. Degradation of nutrients is?
    • -catabolism
    • -releases energy which is CAPTURED & stored as ATP
  40. Synthesis of biomolecules is?
    • -anabolism
    • -uses energy of ATP to do transport, chemical & mechanical work
  41. What is metabolism?
    -a set of all reactions used by living organisms to break down nutrients for energy (catabolism) and synthesize complex biomolecuels from simple precursors (anabolism)
  42. Catabolism is?

    -characterized by?

    • -oxidation
    • -hydrolysis
    • -conversion of biomolecules to C02, H20 and Nh3/urea
  43. Energy released by oxidation is stored in chemical form as?
    NADH, NADPH, and ATP
  44. Anabolism is?

    -characterized by?

    • -reduction
    • -hydration and conversion of small molecules to complex biomolecules
  45. Energy for anabolism is supplied primarily by?
    ATP & NADH
  46. Reducing equivalents for ANABOLISM are supplied primarily by?
  47. Metabolism usually involves?
    multi-step pathways
  48. Pathways have diff forms?
    linear or cyclic or spiral

    -some pathways are reversible
  49. In multistep pathways the overall delta G is?
    the sum of delta G for each step
  50. Multiple steps in pathways means?
    means small amounts of energy change in each step

    -more feasible for biological systems
  51. In catabolism nutrients (fat, sugars, proteins) are OXIDIZED by?
    NAD+ or FAD
  52. In exergonic reactions, some energy is stored in ?
    reduced cofactors (NADH & FADH2) & some enrgy is lost as heat
  53. Reduced cofactors are oxidized by__ in exergonic reaction.
  54. Released energy is used to form ATP from?
    ADP & Pi
  55. In anabolism, small molecule reactants are
    converted to larger more energy rich products
  56. Reducing equivalents for anabolic reactions are supplied by?
    NADPH, NOT nadh
  57. Anabolism:

    Reactions often require?
    reduction of substrates
  58. NAD+/NADH ratio is
    ~100/1, always have NAD+ necessary for catabolism
  59. NADP+/NADPH ratio is?
    1/100- sufficient NADPH for anabolic reactions
  60. ATP(ADP+AMP) ratio is
    ~4/1, sufficient ATP fo anabolism and other energy requiring reactions
  61. High levels of AMP are?
    a signal of energy stress and initiate processes to compensate
  62. Homeostasis:
    cell carries out necessary reactions to maintain these key metabolites in these ratios