What are the steps in the nitrogen cycle?

With the help of the nitrogenase enzyme, atmospheric nitrogen is transformed into ammonium ions, which plants then absorb and use to make amino acids among other things.

The process of nitrifying bacteria, also known as ammonia oxidizing bacteria (AOB) can also convert ammonium ions to nitrite ions. It primarily involves the enzymes nitrite oxidoreductase and ammonia monooxygenase.

Nitrite oxidoreductase facilitates the further oxidation of nitrite ions into nitrate ions.

Read nitrogen assimilation for more information. Nitrate ions are taken and reduced to nitrite and ammonia in turn. The latter can then be incorporated into amino acids via the glutamine synthetase-glutamate synthase pathway, along with the ammonium ions directly taken up from the soil.

In oxygen-poor areas of soil, nitrate ions can also serve as terminal electron acceptors; in this process, known as denitrification, nitrate is converted to nitrogen and then released back into the atmosphere.

See https://tutor.hix.ai for further information.

1. Ammonification 2. Denitrification 3. Assimilation 4. Nitrogen fixation 5.