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All of the learning objectives and key concepts for the second lecture on bioenergetics
what is delta G?
change in Gibbs free energy and is the energy a substance has available to be consumed in a chemical reaction
what is delta H?
change in enthalpy, which is the reaction’s internal heat
what is delta S?
change in entropy, which is the reaction’s disorder
delta H < 0
making bonds, favorable exothermic
delta H > 0
breaking bonds, unfavorable, endothermic
dela S > 0
more disorder, favorable
delta S < 0
less disorder, unfavorable
delta G < 0
favorable, spontaneous, exergonic
delta G > 0
unfavorable, nonspontaneous, endergonic
delta G = 0
equilibrium, no net reaction
how are delta G and delta S related?
they are inverse, so as one increases, the other decreases and vice versa
how are delta G and delta H related?
they are directly proportional to one another, so as one increases, so does the other and vise versa
What equation relates delta G to delta S and delta H
Delta G = delta H - T delta S
what is delta G standard?
the standard free energy, meaning the free energy going from a standard state to equilibrium
how is delta G standard different from delta G?
Standard free energy is used for a standard state and free energy is for any conditions
what is delta G standard prime?
the standard free energy for physiological conditions
what are 3 simplifying assumptions in biochemistry?
[H2O] = 55.5 M
pH = 7.0 so [H+] = 10-7
[Mg2+] = 1 mM
equation using the parameters delta G prime, delta G standard prime, and the actual mass action ratio
delta G prime = delta G standard prime + RT ln([Products]p/[Reactants]r)
equation for finding delta G standard prime from Keq
delta G standard prime = -RT ln (Keq)
negative delta G
moves left to right
positive delta G
moves right to left
Delta G give no information about what?
The rate at which a reaction will go
what is free energy coupling?
when two reactions are needed in order to make the reaction work. This occurs when you have an unfavorable reaction (+delta G), you must couple it with a favorable reaction (-delta G)
what is additivity of free energy change?
when two reactions are coupled, their delta G’s are added as well to see the favorability of the overall reaction. delta G3 = delta G1 + delta G2
what does it mean for a compound to have a large negative free energy of hydrolysis?
This means the compound is energetically favorable to break down, releasing a lot of energy
does breaking the bond for a compound with a large negative free energy of hydrolysis liberate free energy
yes because this process increases entropy and it produces products that are more stable
what is group transfer?
a chemical reaction where a specific functional group is transferred from one molecule to another
what is group transfer potential?
The ability of a molecule to donate it's group to another molecule
what does high group transfer potential mean?
a compound with high group transfer potential is the source of the group that will be transferred, this compound is very unstable and wants to give up its group
What is the free energy of hydrolysis for a compound with high group transfer potential?
Large negative free energy of hydrolysis
What does low group transfer potential mean?
this is the compound that will receive the group from the compound with high group transfer potential and is stable
Why does the terminal phosphoanhydride bond of ATP have such a large negative free energy of hydrolysis?
This is because of the high negative charge density on the phosphate groups. Since there are so many negatively charged oxygens, the ATP wants to give up one of its phosphate groups to become ADP which is more stable.
What are enzymes?
Catalysts that increase the rate of biological reactions to permit life
What do catalysts do?
Increase the rate at which a reaction goes towards equilibrium
What can catalysts not change?
The Keq or the delta G
Reactions always proceed towards ___
Equilibrium
Note 
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