Anaerobic respiration – Wikipedia

respiration using electron acceptors other than oxygen
not to be confused with zymosis Anaerobic respiration is respiration using electron acceptors other than molecular oxygen ( O2 ). Although oxygen is not the final electron acceptor, the march still uses a respiratory electron tape drive chain. [ 1 ] In aerobic organisms undergoing respiration, electrons are shuttled to an electron tape drive chain, and the concluding electron acceptor is oxygen. molecular oxygen is a high-energy [ 2 ] oxidizing agent and, therefore, is an excellent electron acceptor. In anaerobes, other less-oxidizing substances such as nitrate ( NO−
3 ), fumarate ( C
4 ), sulfate ( SO2−
4 ), or sulfur ( S ) are used. These terminal electron acceptors have smaller reduction potentials than O2, meaning that less energy is released per oxidized atom. consequently, anaerobic respiration is less efficient than aerobic.

As compared with agitation [edit ]

Anaerobic cellular breathing and agitation beget ATP in very different ways, and the terms should not be treated as synonym. cellular breathing ( both aerobic and anaerobic ) uses highly reduce chemical compounds such as NADH and FADH2 ( for example produced during glycolysis and the citric acid cycle ) to establish an electrochemical gradient ( much a proton gradient ) across a membrane. This results in an electrical likely or ion concentration dispute across the membrane. The reduce chemical compounds are oxidized by a series of respiratory integral membrane proteins with consecutive increasing decrease potentials, with the final electron acceptor being oxygen ( in aerobic respiration ) or another chemical substance ( in anaerobic respiration ). A proton motivation effect drives protons down the gradient ( across the membrane ) through the proton channel of ATP synthase. The resulting current drives ATP deduction from ADP and inorganic phosphate. zymosis, in contrast, does not use an electrochemical gradient. agitation alternatively entirely uses substrate-level phosphorylation to produce ATP. The electron acceptor NAD+ is regenerated from NADH formed in oxidative steps of the zymosis nerve pathway by the reduction of oxidize compounds. These oxidize compounds are much formed during the agitation pathway itself, but may besides 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 acerb at a late degree in the pathway. In yeast, acetaldehyde is reduced to ethanol to regenerate NAD+. There are two crucial anaerobic microbial methane formation pathways, through carbon dioxide / bicarbonate ( HCO−
3 ) reduction ( respiration ) or acetate rayon agitation. [ 3 ]

ecological importance [edit ]

Anaerobic breathing is a critical component of the global nitrogen, cast-iron, sulfur, and carbon cycles through the decrease of the oxyanions of nitrogen, sulphur, and carbon to more-reduced compounds. The biogeochemical motorbike of these compounds, which depends upon anaerobic respiration, significantly impacts the carbon cycle and global thaw. Anaerobic respiration occurs in many environments, including fresh water and marine sediments, land, subsurface aquifers, deep subsurface environments, and biofilms. even environments, such as dirt, that contain oxygen besides have micro-environments that lack oxygen due to the slow diffusion characteristics of oxygen gasoline. An model of the ecological importance of anaerobic breathing is the use of nitrate as a terminal electron acceptor, or dissimilatory denitrification, which is the main route by which fixate nitrogen is returned to the atmosphere as molecular nitrogen gas. [ 4 ] The denitrification serve is besides identical significant in host-microbe interactions. similar to mitochondria in oxygen-respiring microorganisms, some single-cellular anaerobic ciliates use denitrifying endosymbionts to gain energy. [ 5 ] Another model is methanogenesis, a form of carbon-dioxide breathing, that is used to produce methane boast by anaerobic digestion. Biogenic methane is used as a sustainable alternative to fossil fuels. On the negative side, uncontrolled methanogenesis in landfill sites releases large volumes of methane into the atmosphere, where it acts as a brawny greenhouse gas. [ 6 ] Sulfate breathing produces hydrogen sulfide, which is responsible for the characteristic ‘rotten egg ‘ smell of coastal wetlands and has the capacity to precipitate heavy alloy ions from solution, leading to the deposition of sulfidic alloy ores. [ 7 ]

economic relevance [edit ]

Dissimilatory denitrification is widely used in the removal of nitrate and nitrite from municipal effluent. An overindulgence of nitrate can lead to eutrophication of waterways into which treat body of water is released. Elevated nitrite levels in drinking water can lead to problems ascribable to its toxicity. Denitrification converts both compounds into harmless nitrogen gas. [ 8 ]

English: The model above shows the process of anaerobic respiration through denitrification, which uses nitrogen (in the form of nitrate, NO


) as the electron acceptor. NO


goes through respiratory dehydrogenase and reduces through each step from the ubiquinose through the bc1 complex through the ATP synthase protein as well. Each reductase loses oxygen through each step so that the final product of anaerobic respiration is N2.

1. Cytoplasm
2. Periplasm Compare to the Anaerobic Denitrification ( ETC System ) english : The model above shows the process of anaerobic respiration through, which uses nitrogen ( in the kind of nitrate, ) as the electron acceptor.goes through respiratory dehydrogenase and reduces through each mistreat from the ubiquinose through the bc1 complex through the ATP synthase protein a well. Each reductase loses oxygen through each step therefore that the final product of anaerobic breathing is N1. Cytoplasm2. Periplasm Compare to the aerobic electron transport chain specific types of anaerobic breathing are besides critical in bioremediation, which uses microorganisms to convert toxic chemicals into less-harmful molecules to clean up contaminated beaches, aquifers, lakes, and oceans. For example, toxic arsenate or selenate can be reduced to less toxic compounds by diverse anaerobic bacteria via anaerobic respiration. The reduction of chlorinate chemical pollutants, such as vinyl chloride and carbon tetrachloride, besides occurs through anaerobic breathing. Anaerobic respiration is utilitarian in generating electricity in microbial fuel cells, which employ bacteria that respire hearty electron acceptors ( such as oxidise cast-iron ) to transfer electrons from reduced compounds to an electrode. This process can simultaneously degrade organic carbon godforsaken and beget electricity. [ 9 ]

Examples of electron acceptors in respiration [edit ]

See besides [edit ]

far recitation [edit ]

  • Gregory, Kelvin B.; Bond, Daniel R.; Lovley, Derek R. (June 2004). “Graphite electrodes as electron donors for anaerobic respiration”. Environmental Microbiology. 6 (6): 596–604. doi:10.1111/j.1462-2920.2004.00593.x. ISSN 1462-2912. PMID 15142248.

References [edit ]

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