Biochem thermo

  1. Enthalpy and units
    • tendency toward lowest energy state
    • j/mol or cal/mol
  2. Entropy and units
    • tendency to maximize randomness
    • j/k
  3. calories to joules
    1 cal=4.18 j
  4. what does a postitive delta H signify
    rxn takes up heat
  5. what does a postitive delta S signify
    rxn becomes less ordered
  6. what does a postitive delta G signify
    rxn is unfavorable
  7. 1st law of thermodynamics
    • the total energy of a system remains constant
    • energy cannot be created or destroyed
  8. 2nd law of thermondynamics
    in all spontaneous processes total entropy of the universe increases
  9. thermo equation
  10. ΔG0
    • standard free energy change
    • reactants and products at 1 M or 1 atm
    • T=298 K
  11. ΔG'o
    • biochemist convention
    • rxn pH 7
    • [H+]=10^-7
  12. equation with ΔG0 and ΔG'0
    ΔG0=ΔG'0 + RTln [products]/[reactants]
  13. relationship of Keq and ΔG'0 at equilibrium
  14. difference between kinetics and thermodynamics
    • thermo-where is the eq. pointing
    • kinetics-how fast is the equilibrium approached
  15. high energy compounds
    • large ΔG'0
    • ex: ATP(bond strain), PEP(Product stabilized by isomerization), Phospocreatin (product resonance stabilized), Acyl Phosphates (product ionization stabilized)
    • release of Pi is favorable
  16. bond stability between thiol ester and oxoesters
    thiol ester less stable than oxoester because of poor overlap between 3p e- orbital of sulfur and sp orbital of carbon
  17. more -ΔG'0 vs less- ΔG'0 in phosporylation
    more - compounds can phosphorylate while less neg can be phosphorylated
Card Set
Biochem thermo
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