Biochemistry

Lecture 2

Bioenergetics• “The study of energy transductions in

living cells”• Biological processes obey the laws of

thermodynamics, i.e.:– Energy isn’t created or destroyed– Entropy of the system always increases

CellReactants Products

Thermodynamics

STHG

+6+ 6 6

Free Energy in Bioenergetics

QRTGG ln'0

eqKRTG ln'0

At equilibrium, ΔG = 0 and Q becomes Keq

or

RTGeq eK /'0

Structural differences between products and reactants

Concentration differences between products and reactants

Organic Chemistry, revisited

Nucleophilic Bond Formation

Phosphate and ATP

ATP Hydrolysis

Oxidation and Reduction

Electron Carriers