# Thermodynamics/Biochemistry

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1. System
is the part of universe that is under study
2. Surroundings
is everything else in the universe
3. Isolated system
can’t exchange matter or energy with the surroundings
4. Closed system
it is possible that it will exchange energy, but not matter, with the surroundings
5. Open system
may exchange matter, energy, or both with the surroundings
6. First Law of thermodynamics
in an isolated system, the energy is not created nor destroyed, it is conserved
7. Internal Energy (E)
keeps track of the heat transfer and work performed in thermodynamics systems
8. First Law of thermodynamics
∆E =
E2 – E1 = q + w
9. Mechanical work
movement through some distance caused by the application of the force
10. Relationship of work with pressure and volume
w = -P∆V
11. If the work is not done by the system the sign is
positive
12. If the work is done by the system the sign is
negative
13. Types of work
• mechanical
• electrical
• magnetic
• chemical
14. Enthalpy
• heat exchange at constant pressure
• H = E + PV
• H = q
15. For solutes in a solution, the standard state is .
• normally unit activity or 1M concentration
• “ ° ”, ∆E °, ∆H°, etc
16. Second Law of Thermodynamics
the system tends to proceed from an ordered state to a disordered state
17. Entropy (∆S)
measure of disorder and randomness in the system or surroundings
18. Ordered state
low entropy state
19. Disordered
high entropy state
20. Reactions with large positive entropy changes are
more likely to occur than reactions with small positive entropy
21. Third Law of Thermodynamics
the entropy of any crystalline, perfectly ordered substance must approach zero as the temperature approaches 0K
22. Heat capacity (Cp)
is the amount of heat needed for one mole of any substance to raise the temperature by one degree
23. One can calculate the entropy change if the
• enthalpy and the free energy change are known
• ∆G = ∆ H - T∆S
24. ∆G = 0
the reaction is in equilibrium
25. If ∆G < 0
the process goes toward the direction written. (exergonic)
26. If ∆G > 0
the process goes toward the reverse direction. (endergonic)
27. Positive ∆H for the protein unfolding
breaking of hydrogen bonds or exposure of hydrophobic groups to water
28. Phototropic organisms
absorb light energy directly form the Sun
29. Chemotrophic organisms
feed on phototropic organisms and release store energy in a series of oxidative reactions
30. Chemical reasons for large ∆G°’ values
• destabilization of the reactant due to electrostatic repulsions
• stabilization of the products by ionization and resonance
• entropy factors due to hydrolysis and ionization.
31. Enol Phosphates
important intermediate of carbohydrate metabolism
32. In hydrolysis as pH increases, ∆G°becomes
more negative for every pH unit increase
33. If ∆E°’ is negative
the flow goes toward the reference cell because the sample donates electrons
34. If ∆E°’ is positive
the flow goes toward the sample cell because the sample accepts electrons
 Author: stefanyoli787 ID: 237584 Card Set: Thermodynamics/Biochemistry Updated: 2013-09-29 00:55:23 Tags: Thermodinamics Biochemistry Folders: Description: Biochemistry, Thermodinamics, systems Show Answers: