Key Terms
Metabolism
All chemical reactions in a cell.
Bioenergetics
Study of energy flow through living systems.
Metabolic pathway
A series of step-by-step biochemical reactions that convert a starting molecule (substrate) into a final product through
Breakdown of glucose (catabolic)
C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
Notice
These are exact reversals of each other.
Energy
The ability to do work.
Kinetic energy
Energy of motion.
Potential energy
Stored energy; energy due to position or structure.
Gibbs free energy (G)
The usable energy available to do work after accounting for entropy losses.
Delta G (dG)
The change in free energy during a reaction.
Formula
DG = dH - T(dS)
Exergonic
Reaction that releases energy; negative dG.
Endergonic
Reaction that requires energy input; positive dG.
Activation energy (Ea)
Minimum energy required to start a reaction; always positive.
Transition state
High-energy, unstable intermediate between reactants and products; peak of the energy diagram.