what does not fix atmospheric nitrogen to nitrates?
Answers
Answer:Non-biological
Lightning heats the air around it breaking the bonds of N
2 starting the formation of nitrous acid.
Nitrogen can be fixed by lightning that converts nitrogen gas (N
2) and oxygen gas (O
2) present in the atmosphere into NO
x (nitrogen oxides). NO
x may react with water to make nitrous acid or nitric acid, which seeps into the soil, where it makes nitrate, which is of use to plants. Nitrogen in the atmosphere is highly stable and nonreactive due to the triple bond between atoms in the N
2 molecule.[7] Lightning produces enough energy and heat to break this bond[7] allowing nitrogen atoms to react with oxygen, forming NO
x. These compounds cannot be used by plants, but as this molecule cools, it reacts with oxygen to form NO
2.[8] This molecule in turn reacts with water to produce HNO
3 (nitric acid), or its ion NO−
3 (nitrate), which is usable by plants.[9][7]
Biological
Schematic representation of the nitrogen cycle. Abiotic nitrogen fixation has been omitted.
Biological nitrogen fixation was discovered by German agronomist Hermann Hellriegel[10] and was fully described by Dutch microbiologist Martinus Beijerinck.[11]
"The protracted investigations of the relation of plants to the acquisition of nitrogen begun by Saussure, Ville, Lawes and Gilbert and others culminated in the discover of symbiotic fixation by Hellriegel and Wilfarth in 1887."[12]
"Experiments by Bossingault in 1855 and Pugh, Gilbert & Lawes in 1887 had shown that nitrogen did not enter the plant directly. The discovery of the role of nitrogen fixing bacteria by Herman Hellriegel and Herman Wilfarth in 1886-8 would open a new era of soil science."[13]
Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by a nitrogenase enzyme.[1] The overall reaction for BNF is:
{\displaystyle {\ce {N2 + 16ATP + 8e- + 8H+ -> 2NH3 +H2 + 16ADP + 16}}}{\displaystyle {\ce {N2 + 16ATP + 8e- + 8H+ -> 2NH3 +H2 + 16ADP + 16}}}{\displaystyle {\text{P}}_{i}}{\displaystyle {\text{P}}_{i}}
The process is coupled to the hydrolysis of 16 equivalents of ATP and is accompanied by the co-formation of one equivalent of H
2.[14] The conversion of N
2 into ammonia occurs at a metal cluster called FeMoco, an abbreviation for the iron-molybdenum cofactor. The mechanism proceeds via a series of protonation and reduction steps wherein the FeMoco active site hydrogenates the N
2 substrate.[15] In free-living diazotrophs, nitrogenase-generated ammonia is assimilated into glutamate through the glutamine synthetase/glutamate synthase pathway. The microbial nif genes required for nitrogen fixation are widely distributed in diverse environments.[16][17]
Nitrogenases are rapidly degraded by oxygen. For this reason, many bacteria cease production of the enzyme in the presence of oxygen. Many nitrogen-fixing organisms exist only in anaerobic conditions, respiring to draw down oxygen levels, or binding the oxygen with a protein such as leghemoglobin.[1]
Please mark me as brainliest