what is nitrogen fixation?

Answer 1

Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds (such as, notably, ammonia, nitrate and nitrogen dioxide) useful for other chemical processes.
Nitrogen fixation is performed naturally by a number of different prokaryotes, including bacteria, and actinobacteria certain types of anaerobic bacteria. Microorganisms that fix nitrogen are called diazotrophs. Some higher plants, and some animals (termites), have formed associations with diazotrophs.
Nitrogen fixation also occurs as a result of non-biological processes. These include lightning, industrially through the Haber-Bosch Process, and combustion.
Biological Nitrogen Fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by a pair of bacterial enzymes called nitrogenase. The formula for BNF is:

N2 + 8H+ + 8e− + 16 ATP → 2NH3 + H2 + 16ADP + 16 Pi
Although ammonia (NH3) is the direct product of this reaction, it is quickly ionized to ammonium (NH4+). In free-living diazotrophs, the nitrogenase-generated ammonium is assimilated into glutamate through the glutamine synthetase/glutamate synthase pathway.

Answer 2

Nitrogen as a gas is virtually useless to living things. Although Nitrogen is the most common gas in the air we breathe it in with one breath and exhale it unused. Nitrogen compounds on the other hand, nitrogen atoms chemically combined with atoms of other elements are essential to life. Certain bacteria living in the ground around plant roots called nitrogen fixing bacteria have the ability to combine gaseous nitrogen from the air with elements from the soil to form chemicals necessary for plant and animal life. This is called nitrogen fixation and without it life on earth would probably not be possible. Other natural processes fix nitrogen but not in the quantities needed by life as it exists on this planet. BTW. The word "fix" did not originally mean to repair. It meant to attach, put together or keep in one spot. It probably came to be used to mean repair because an object which is broken often ends up in two or more parts. When you repair such an object you reattach or fix the parts. These bacteria attach or fix the nitrogen.

Answer 3

any natural or industrial process that causes free nitrogen, which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more reactive nitrogen compounds such as ammonia, nitrates, or nitrites.

Under ordinary conditions nitrogen does not react with other elements. Yet nitrogenous compounds are found in all fertile soils