In biology, anaerobic respiration is a way for an organism to produce usable energy without the involvement of oxygen; it is respiration without oxygen.^[1] Respiration is a redox reaction that processes energy in a form usable by an organism, chiefly the process of producing ATP^[2], the "universal energy currency of life".^[3] It employs an electron transport chain, with inorganic molecules other than oxygen used as a final electron acceptor.

[edit] Examples of anaerobic respiration

gsup>+, ΔG⁰' = -1796 kJ

glucose + 3SO₄^2- + 3H⁺ 6HCO₃^- + 3SH^-, ΔG⁰' = -453 kJ

glucose + 12S + 12H₂O 6HCO₃^- + 12HS^- + 18H⁺, ΔG⁰' = -333 kJ

All of these terminal electron acceptors have smaller reduction potentials than O₂, meaning that less energy is released per oxidised molecule of primary electron donor than in aerobic respiration (i.e. it is less energetically efficient). The ΔG⁰' of aerobic respiration is -2844 kJ.

[edit] Commercial applications of anaerobic respiration

• Anaerobic digestion
• Mechanical biological treatment

[edit] Notes

1. ^ Henderson's Dictionary of Biological Terms 10th Edition, Eleanor Lawrence, p25
2. ^ Henderson's Dictionary of Biological Terms 10th Edition, Eleanor Lawrence, p467
3. ^ Power Suicide, Mitochondria and the Meaning of Life, Nick Lane, p80

v • d • e Cellular Respiration Aerobic Respiration Glycolysis → Pyruvate Decarboxylation → Citric Acid Cycle → Oxidative Phosphorylation (Electron Transport Chain + ATP synthase) Anaerobic Respiration Glycolysis → Lactic Acid Fermentation or Ethanol Fermentation

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v • d • e Metabolism map Glucuronate metabolism Pentose interconversion Inositol metabolism Cellulose and sucrose metabolism Starch and glycogen metabolism Other sugar metabolism Pentose phosphate pathway Glycolysis and Gluconeogenesis Amino sugars metabolism Small amino acid synthesis Branched amino acid synthesis Purine biosynthesis Histidine metabolism Aromatic amino acid synthesis Pyruvate decarboxylation Fermentation Fatty acid metabolism Urea cycle Aspartate amino acid group synthesis Porphyrins and corrinoids metabolism Citric acid cycle Glutamate amino acid group synthesis Pyrimidine biosynthesis  v • d • e  All pathway labels on this image are links, simply click to access the article. A high resolution labeled version of this image is available here.