Bio CH 6 Energy/Metabolism

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Bio CH 6 Energy/Metabolism
2012-02-26 20:18:53

Chapter 6
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  1. Electrons movement:
    • oxidation/reduction or REDOX reactions
    • Gains electron = reduction
    • Loses electron = oxidation (reduction reactions)

    Molecule reduced has higher energy

    always occur together because every electron that is lost through oxidation is gained by reduction.
  2. Energy:
    "capacity to do work"

    Free energy: energy available to do work in any system.
  3. Thermodynamics:
    • Science of energy exchanges/changes
    • measured by heat... kilocalore kcal
    • 1 kcal = 1000 calories
    • 1 calorie is the heat required to raise the temp. of water 1 degree Celsius
  4. Energy can be in 1 or 2 states:
    • 1) Kinectic: movement, motion
    • 2) Potential: stored
  5. 1st law of thermodynamics:
    Energy can be changed from 1 form to another, but not created or destroyed it can only change from one form to another (potential to kenetic). Total amount of energy in universe stays constant.

    • Form:
    • Heat- Kinetic/potential
    • Light- Kinectic
    • Atomic energy- Potential

    during each conversion energy is lost as heat.
  6. 2nd law of thermodynamics
    In energy conversions the potential energy of the final stage will be less than that of the initial state (some energy given off (most as heat)

    • Disorder in universe (entropy) is continously increasing.
    • Exergonic
    • Endergonic
  7. Exergonic reactions: FIG. 4.6 and 6.5
    Energy Given Off
  8. Endergonic: FIG. 4.6 and 6.5
    Requires energy. Must be coupled to exergonic one
  9. Entropy/Enthalpy
    Measure of disorder or randomness

    C6H12O6 (glucose) ----> 6CO2 + 6H20 + energy in motochondria "catabolic reactions"

    • H= heat content, potential energy, enthalpy
    • ^H = change in H
    • G= Gibbs free energy, available/usable energy
    • ^G=^H-T^S
    • T= Temperture
    • S=Entrpopy

    Usable energy is reduced due to increase in entropy
  10. Enzymes:
    Involved in virtually all reactions (metabolism)
  11. Enzyme synthetic reactions
    endergonic 'take in energy'

  12. Enzyme breakdown reactions
    exergonic 'give off energy'

  13. Enzymes Structure:
    • globular protein made of 1 or more chains
    • -Primary, Secondary, Tertiary, Quat. Structures

    Active Site and Substrate Molecules (FIG 6.8)
  14. Speed of Enzymes
    1000 substrates molecules per second

    Enzymes are acting as catalysts (speed up reactions, not used up)

  15. Regulation/ Control of Enzymes
    • 1) production of enzyme
    • 2) some enymes have control site (allosterksite)
    • -End Point
    • -Feedback
    • 3)Substrate of molecule availble?
    • 4) "cofactors" available
    • 5) pH correct? optimum pH
    • 6) Temp. correct
  16. "cofactors"
    • Molecules that help enzymes (carry electrons)
    • 1) some are organic (coenzmes)
    • -vitamins/coenzymes B6,B12 (electron carriers)
    • 2) inorganic molecules
  17. Etc. Enzymes
    • -some are free in cytoplasm / or attached
    • -some are single / or in groups
  18. Are there any non-protein (non-enzymes catalyst?
    YES - RNA (ribozymes) help reactions
  19. ATP
    • Energy Currency Molecule
    • -endergonic reaction: J & K ----> L
    • J,K,L = compounds

    • J&K need enrergy of 10kcal/mol
    • this reaction neds to be coupled to exorganig reaction

    • ATP -----> ADP + P (phosphours group)
    • -7.3kcal/mole released

    needs 10kcal but only has 7.3 so need 2 ATP's to get to 10

    ATP is constantly being made and used.
  20. Origin of specifin biochemical pathway:
    • 1st organism (cells) -used organic molecules in H20 around them
    • Example: R=simple comound, if R begins to run short selection for cell who could help make R begins =T+S....if T begins to run short...F+G is found to help (works backwards)

    F+G ---> (T)+S----> R
  21. Gibbs Free Energy
    ^G = ^H-^T^S

    • G= gibbs free energy, available energy
    • T= Temp
    • S= Entropy
  22. Allosteric Site
    Part of enzyme away from active site, on/off switch
  23. Active Site
    Region of enzyme surface, substrates bind, lowering activation energy required and fascilitates function.
  24. Feedback Inhibitor
    Control mechanism, concentratration inhibits sythesis
  25. Inhibitors
    Substance binds to enzyme and decreases its activity
  26. Activators
    Binds to enzyme and increases activity
  27. Graph of Reactants/Products: Endergonic/Exergonic

    • Endergonic- Products contain more energy than reactants
    • Exergonic- products contain less energy than reactants
  28. Catalysts and activation graph:

    lowers activation energy needed to initiate reaction (enzymes act as catlysts)
  29. Amount of energy required to break or form chemical bond:
    Activation energy
  30. Excess energy released as:
  31. Structure of ATP:
    • 1.) 5 Carbon Sugar ribose
    • 2.) 2 carbon nitrogen
    • 3.) chain of three phosphates