Anaerobic Respiration - Anaerobic Respiration As Compared To Fermentation

Anaerobic Respiration As Compared To Fermentation

Cellular respiration (both aerobic and anaerobic) utilizes highly reduced species such as NADH and FADH2 (for example produced during glycolysis and the citric acid cycle) to establish an electrochemical gradient (often a proton gradient) across a membrane, resulting in an electrical potential or ion concentration difference across the membrane. The reduced species are oxidized by a series of respiratory integral membrane proteins with sequentially increasing reduction potentials with the final electron acceptor being oxygen (in aerobic respiration) or another species (in anaerobic respiration). The membrane in question is the inner mitochondrial membrane in eukaryotes and the cell membrane in prokaryotes. A proton motive force or pmf drives protons down the gradient (across the membrane) through the proton channel of ATP synthase. The resulting current drives ATP synthesis from ADP and inorganic phosphate.

Fermentation in contrast, does not utilize an electrochemical gradient. Fermentation instead only uses substrate-level phosphorylation to produce ATP. The electron acceptor NAD+ is regenerated from NADH formed in oxidative steps of the fermentation pathway by the reduction of oxidized compounds. These oxidized compounds are often formed during the fermentation pathway itself, but may also be external. For example, in homofermentative lactic acid bacteria, NADH formed during the oxidation of glyceraldehyde-3-phosphate is oxidized back to NAD+ by the reduction of pyruvate to lactic acid at a later stage in the pathway. In yeast, acetaldehyde is reduced to ethanol.

Read more about this topic:  Anaerobic Respiration

Famous quotes containing the words fermentation and/or compared:

    A tree is made to live in peace in the color of day and in friendship with the sun, the wind and the rain. Its roots plunge in the fat fermentation of the soil, sucking in its elemental humors, its fortifying juices. Trees always seem lost in a great tranquil dream. The dark rising sap makes them groan in the warm afternoons. A tree is a living being that knows the course of the clouds and presses the storms because it is full of birds’ nests.
    Jacques Roumain (1907–1945)

    Heroism—that is the disposition of a man who aspires to a goal compared to which he himself is wholly insignificant. Heroism is the good will to self-destruction.
    Friedrich Nietzsche (1844–1900)