Nitrogen is important as organisms need to use it to build important cellular components. However, most organisms are unable to use nitrogen found in the environment because nitrogen is inert. Therefore, nitrogen needs to be fixed or combined with another chemical.
Atmospheric nitrogen is composed of two nitrogen atoms joined by a triple covalent bond. For organisms to utilize nitrogen, it must be broken down and combined with another chemical. Some microorganisms are able to produce nitrogenase, an enzyme that breaks down atmospheric nitrogen and adds three hydrogen atoms to each nitrogen molecule.
Nitrogen is an important part of building amino acids and nucleic acids, both which are critical for maintaining life. Amino acids and nucleic acids are essential building blocks for cellular growth and repair in organisms in the form of protein. Without nitrogen, many life processes cannot be sustained.