BCHM-3050 Lecture Notes - Lecture 2: Living Systems, Phosphodiester Bond, Thermodynamics
19 May 2018
School
Department
Course
Professor
Equilibrium v homeostasis
Both: concentration of product and reactants is constant
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Homeostatic conditions: far from equilibrium
Energy is required maintain
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Controlled system
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Q far from K
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Value of Q
Value of ∆G
Favored direction
< K
< 0
forward
>K
>0
reverse
K = Q
0
neither
Coupling, water, buffered solns, and biochem stp
Coupling: meshing of rxns that will not go in the forward direction and
rxn that will go in the forward direction to make the unfavorable rxns
become favorable
Living systems use this
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Living systems = aqueous
Buffered
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Stp of biochem:
T = 273.15
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R = 1 atm
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Concentration = 1 M
For H+ = 10^-7 M
§
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ATP
ATP: common energy currency
Large energy in phosphodiester bonds
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ATP to ADP = favorable process
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Why are certain compounds so energy rich?
Resonance stabilization of products
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Charge repulsion in reactants
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Tautomerization of products
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∆G˚' for redox rxns
Standard reduction potential (E˚): tendency of specie gaining e-
Large E˚ = larger tendency of e- carrier to become reduced
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Positive E˚ is favorable
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∆G˚= -nF∆E˚
∆E˚ = [E˚ reduction + E˚ Oxidation]
N = # e- transferred (usually 1 or 2)
F = 96.5 kj/mol*V
Chapter 3: Thermodynamics and biochem
Friday, May 18, 2018
4:54 PM
