Bioenergetics Flashcards
Entropy
randomness associated with a given system
∆S = + , favorable, disorder increases in a system
∆S = - , unfavorable, disorder decreases in a system
Enthalpy
measure of heat content of a system
Exothermic reaction vs. endothermic raction
Exothermic = ∆H (-), release heat, favorable Endothermic = ∆H (+) absorb heat, unfavorable
Gibbs Free Energy (G)
Amount of thermodynamic energy in a system that can be converted into work at a given temperature and pressure
High energy compounds
compounds with bonds that release greater than 7 kcal/mol of energy when broken (∆G= -7)
Oxidation-reduction reaction
A chemical reaction involving the transfer of electrons away from one compound (oxidized compound, e- donor) to another compound (reduced compound, e- acceptor)
First Law of Thermodynamics
Energy conservation:
-cannot be created or destroyed, only converted
Second Law of Thermodynamics
The entropy of the universe is constantly increasing
4 kinds of kinetic energy
kinetic = energy of motion
1) radiant
2) thermal
3) mechanical
4) electric
4 kinds of potential energy
potential = stored energy
1) stored in chemical bonds
2) stored in concentration gradients
3) stored in electric fields from charge separation
4) stored in redox pairs
Radiant energy
carried in photons from the sun
Electric energy
Energy movement of charged particles down gradients of electric potential
3 Equations we have to memorize about Gibbs Free Energy
1) ∆G = ∆H - T∆S
(T in KELVIN)
2) ∆G = -nF∆E
(n=#electrons transferred), (F=Faraday constant), (∆E=difference in reduction potential in VOLTS)
3) ∆G = ∆Go + (RT) (ln [products]/[reactants]
(R=gas constant) (∆Go=free energy under standard conditions)
4) ∆Go = (-RT) ln (Keq)
∆G 0 =
∆G = 0 =
∆G 0 = not spontaneous
∆G = 0 = at equilibrium
∆E = ?
Eo electron acceptor - Eo electron donor
