出典:Wikipedia
出典:『Wikipedia』 (2011/06/15 04:11 UTC 版)
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen (N2) in the atmosphere is converted into ammonia (NH3). This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and amino acids for proteins. Nitrogen fixation also refers to other biological conversions of nitrogen, such as its conversion to nitrogen dioxide.