breakdown of complex molecules into smaller ones
reactions that build cells
Gibbs free energy change, ∆G.
The direction of a reaction can be predicted by a thermodynamic quantity called Gibbs free energy change, ∆G.
Change in enthalpy, the heat energy absorbed or released
∆H-driven reactions release heat.
∆S-driven reactions depend on temperature.
- Product of temperature and entropy change
- -If ∆G< 0, the process may go forward.
- -If ∆G> 0, the reaction will go in reverse.
Intrinsic properties of a reaction
The changes of ΔHand ΔS contributing to ΔG
Molecules that gain or release small amounts of energy in reversible reactions
Examples: NADH and ATP
an oxidizing agent
contains a base, sugar, and three phosphates
ATP can transfer energy to cell processes in three different ways:
- 1.Hydrolysis-releasing phosphate (Pi)
- 2.Hydrolysis-releasing pyrophosphate (PPi)
- 3.Phosphorylation of an organic molecule
- carries two or three times as much energy as ATP.
- -It also donates and accepts electrons.
- -NADH is the reduced form.
- -NAD+is the oxidized form.
Flavine adenine dinucleotide
- is another related coenzyme that can transfer electrons
- Unlike NAD+, FAD is reduced by two electronsand two protons
partial breakdown of organic food without net electron transfer to an inorganic terminal electron acceptor
complete breakdown of organic molecules with electron transfer to a terminal electron acceptor such as O2
catabolism is conducted with a “boost” from light