- The electron transport system generates a
- “proton motive force” that drives protons across
- the membrane.
- - The PMF stores energy to make ATP.
Organotrophy (or chemoorganotrophy):
Lithotrophy (or chemolithotrophy):
- 1. Organotrophy (or chemoorganotrophy):
- involves organic electron donors and inorganic
- or organic terminal electron acceptors
- 2. Lithotrophy (or chemolithotrophy): involves
- inorganic electron donors and inorganic or
- organic terminal acceptors
- 3. Phototrophy: involves light capture by
- chlorophyll, usually coupled to splitting of H2S
- or H2O or organic molecules
- electron transport proteins
- - They oxidize one substrate (removing electrons)
- and reduce another (donating electrons).
- In redox reactions, the ∆G values are proportional to
- the reduction potential (E) between the oxidized
- form (e– acceptor) and its reduced form (e– donor).
- - The reduction potential is a measure of the
- tendency of a molecule to accept electrons.
- A reaction is favored by positive values of E, which
- yield negative values of ∆G.
- The standard reduction potential assumes all
- reactants and products equal 1 M at pH 7.
proton potential ∆p
∆p = ∆ψ – 60∆pH
- - The electrical potential (∆ψ) arises from the
- separation of charge between the cytoplasm and
- solution outside the cell membrane.
- - The pH difference (∆pH) is the log ratio of
- external to internal chemical concentration of H+.
- Includes at least three functional components:
- 1. An initial substrate oxidoreductase
- 2. A mobile electron carrier
- 3. A terminal oxidase