Entropy: definition
Energy that cannot be used to do work. Measure of disorder. Price you pay for the work you do.
Enthalpy:
Energy that can be used to do work. Total energy in a thermodynamic system.
Catabolism
Breaking down energy-containing molecules like food to energy-depleted molecules like CO2, H2O, and NH3.
Electron carriers
NADH, NADPH, FADH2. (ATP can also store energy)
anabolism
AA, sugars, Fatty acids, nitrogenous bases -> proteins, polysaccharides, lipids, nucleic acids
Free Energy
The component of the total energy of a system that can do work at constant temperature and pressure
High energy compounds
ATP (phospoanhydride bond, acetyl CoA (thioester bond), Phosphocreatin (P-N) Phophoenolpyruvate (C-O-P)
Examples of kinetic energy in cell
Radiant: from sun.
Thermal: some reactions need a certain heat or thermal energy to proceed
Mechanical energy: movement of cells and cell components
Electric Energy: movement of charged particles down a electrical potential gradients
Examples of potential energy in cell
Stored in: Chemical bonds, electrical potential gradients (electric fields), concentration gradients, redox pairs
First law of Thermodynamics
Energy cannot be created nor destroyed. It can be transferred and converted.
Second law of thermodynamics
Entropy of the Universe is always increasing.
Equation relating Free Energy to Enthalpy and Entropy (for a chemical reaction)
ΔG=ΔH - TΔS
Equation relating Free Energy to product/reactant concentrations (for a concentration gradient)
ΔG = ΔGo + RT ln [products]/[reactants]
Equation relating free energy to equilibrium constant
ΔGo = -RT ln Keq
Equation relating Free Energy to reduction potential
ΔG = -nFΔE
rate of a reaction
Forward: proportional to product of reactant concentrations
Reverse: proportional to product of product concentrations
