Examples of nitrogen fixation in the following topics:
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- Nitrogen fixation also refers to other biological conversions of nitrogen, such as its conversion to nitrogen dioxide.
- Nitrogen fixation is a process by which nitrogen (N2) in the atmosphere is converted into ammonia (NH3).
- Fixation processes free up the nitrogen atoms from their diatomic form (N2) to be used in other ways.
- Therefore, nitrogen fixation is essential for agriculture and the manufacture of fertilizer.
- Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase.
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- Nitrogen fixation carried out by bacteria helps farmers yield healthy crops.
- Hermann Hellriegel (1831-1895), a noted German agricultural chemist, discovered that leguminous plants took atmospheric nitrogen and replenished the ammonium in the soil through the process now known as nitrogen fixation.
- He found that the nodules on the roots of legumes are the location where nitrogen fixation takes place.
- Hellriegel did not determine what factors in the root nodules carried out nitrogen fixation.
- These rhizobia perform the chemical processes of nitrogen fixation.
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- Through control of gene expression, nitrogen fixing bacteria can turn on and off the proteins needed for nitrogen fixation.
- The fixation of atmospheric nitrogen (N2) is a very energy intensive endeavor.
- The nif genes are genes encoding enzymes involved in the fixation of atmospheric nitrogen.
- Nitrogen fixation is regulated by nif regulon, which is a set of seven operons which includes 17 nif genes.
- Discuss the role of the nif genes in controlling nitrogen fixation
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- Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase.
- While the equilibrium formation of ammonia from molecular hydrogen and nitrogen has an overall negative enthalpy of reaction (i.e. it gives off energy), the energy barrier to activation is very high without the assistance of catalysis, which is done by nitrogenases.
- The association of nitrogenase component I and II and later dissociation occurs several times to allow the fixation of one N2 molecule (see step B and D).
- Nitrogenase ultimately bonds each atom of nitrogen to three hydrogen atoms to form ammonia (NH3).
- Distinguish between component I and II of the nitrogenase enzyme and its role in biological nitrogen fixation
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- The nitrogen cycle is the process by which nitrogen is converted from organic to inorganic forms; many steps are performed by microbes.
- The nitrogen cycle describes the conversion of nitrogen between different chemical forms.
- Nitrogen is essential for the formation of amino acids and nucleotides.
- Fixation: In order for organisms to use atmospheric nitrogen (N2), it must be "fixed" or converted into ammonia (NH3).
- This can happen occasionally through a lightning strike, but the bulk of nitrogen fixation is done by free living or symbiotic bacteria.
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- The key collective metabolic processes of microbes (including nitrogen fixation, carbon fixation, methane metabolism, and sulfur metabolism) effectively control global biogeochemical cycling.
- The transformative process by which carbon dioxide is taken up from the atmospheric reservoir and "fixed" into organic substances is called carbon fixation.
- The Earth's atmosphere is primarily composed of nitrogen, but atmospheric nitrogen (N2) is relatively unusable for biological organisms.
- Consequently, chemical processing of nitrogen (or nitrogen fixation) is necessary to convert gaseous nitrogen into forms that living organisms can use.
- Almost all of the nitrogen fixation that occurs on the planet is carried out by bacteria that have the enzyme nitrogenase, which combines N2 with hydrogen to produce a useful form of nitrogen (such as ammonia).
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- They play an important role in the nitrogen cycle by increasing the availability of nitrogen to plants while limiting carbon dioxide fixation.
- Betaproteobacteria play a role in nitrogen fixation in various types of plants, oxidizing ammonium to produce nitrite- an important chemical for plant function.
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- Nitrogen fixing bacteria have different strategies to reduce oxygen levels, which interfere with nitrogenase function.
- Central to nitrogen fixation (N2 to NH3) are the enzymes that do the actual fixation, these are known as nitrogenases.
- Many rhizobia, nitrogen fixing bacteria, live in a symbiotic relationship with plants known as legumes.
- Leghemoglobin is a nitrogen or oxygen carrier; naturally occurring oxygen and nitrogen interact similarly with this protein.
- The protein and heme come together to function , allowing the bacteria to fix-nitrogen, giving the plant usable nitrogen and thus the plant provides the rhizobia a home.
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- Anammox, an abbreviation for ANaerobic AMMonium OXidation, is a globally significant microbial process of the nitrogen cycle.
- Anammox, an abbreviation for ANaerobic AMMonium OXidation , is a globally significant microbial process of the nitrogen cycle.
- Anammox organisms are autotrophs although the mechanism for carbon dioxide fixation is still unclear.
- Because of this property, these organisms could be used industrially to remove nitrogen in wastewater treatment processes.
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- Nitrobacter plays an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil.
- Nitrification is an important step in the nitrogen cycle in soil.
- Nitrification is a process of nitrogen compound oxidation (effectively, loss of electrons from the nitrogen atom to the oxygen atoms):
- As in sulfur and iron oxidation, NADH for carbon dioxide fixation using the Calvin cycle is generated by reverse electron flow, thereby placing a further metabolic burden on an already energy-poor process.
- Schematic representation of the flow of nitrogen through the environment.