Biochem 3300 - Metabolism III PI

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  1. The first two laws of thermodynamics/bioenergetics
    • First law - Energy is always conserved
    • Second law - Entropy always increases
  2. Gibbs free energy equation & units
    ΔG = ΔH - TΔS

    • ΔG - J mol-1
    • ΔH - J mol-1
    • T - °K
    • ΔS - J K mol-1
  3. What is Gibbs free energy?
    Energy available to do work
  4. What is entropy
    Measure of randomness of a system
  5. How does ΔG relate to ΔG°
    ΔG = ΔG° + RT ln{[C]c[D]d/([A]a[B]b)}
  6. When does ΔG = ΔG°
    When the equilibrium ratio = 1
  7. Equation for Keq
    Keq = [C]c[D]d/([A]a[B]b)
  8. What are transformed standard constants?
    • Constants used in Chemistry of Physics that have been transformed for Biochemistry
    • ΔG'°, K'eq
  9. What are some requisites for transformed standard constants?
    Invarient H2O, H+ or Mg2+
  10. Is ΔG constant?
    No, it depends on product/reaction concentrations
  11. Is ΔG° constant?
  12. Energy coupling
    • A -> B   ΔG1
    • B -> C   ΔG2

    ΔG'°Total = ΔG1'° + ΔG2
  13. What is an example of energy coupling?
    Most reactions involving ATP
  14. Hexokinase
    Phosphorylates glucose on carbon 6
  15. Esters
    Stable products from reactions between a carboxylic acid and an  alcohol
  16. Anhydride
    • High energy bonds formed from two carboxylic acids eliminating water
    • Easily hydrated (hydrolysis)
  17. ATP phosphate bonds
    • Beta and Gamma - Phosphoanhydride
    • Alpha - Phosphoester
  18. Why are resonance structures stabillizing?
    They minimize local charges
  19. How does Mg2+ assist ATP hydrolysis
    It partially shields the negative charges and causes a conformational change
  20. High group transfer potential
    Associated with high energy bonds
  21. What is pyrophosphate? Why is it useful?
    • p~p
    • It is useful because it's cleavage from ATP is irreversible (used in RNA polymerase)
  22. Why are ATP analogues useful?
    • Freeze coupled mechanisms to examine them
    • Freeze ATP hydrolyzing enzymes to examine them
  23. Is polyphosphate ( ~P~P~P~P~P~P~) found in cells?
    Yes, as energy storage or a chelating agent
  24. What enzyme produces polyphosphate?
    • polyphosphate kinase-1
    • ATP + polyPn <--(mg2+)--> ADP + polyPn+1
  25. PEP
Card Set:
Biochem 3300 - Metabolism III PI
2016-01-25 02:05:55

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