||This article has multiple issues. Please help improve it or
discuss these issues on the talk page. Anaerobic respiration is
a form of respiration using electron acceptors other than
oxygen. Although oxygen is not used as the final electron
acceptor, the process still uses a respiratory electron
transport chain; it is respiration without oxygen. In order for
the electron transport chain to function, an exogenous final
electron acceptor must be present to allow electrons to pass
through the system. In aerobic organisms, this final electron
acceptor is oxygen. Molecular oxygen is a highly oxidizing agent
and, therefore, is an excellent acceptor. In anaerobes, other
less-oxidizing substances such as sulfate (SO42-), nitrate
(NO3-), sulfur (S), or fumarate are used. These terminal
electron acceptors have smaller reduction potentials than O2,
meaning that less energy is released per oxidized molecule.
Anaerobic respiration is, therefore, in general energetically
less efficient than aerobic respiration. Anaerobic