Why do proteins and amino acids require nitrogen?

Nitrogen is a fundamental chemical element required for life because it is an essential building block of amino acids, which in turn form proteins. These molecules are critical to the composition and function of all living organisms.1

In the structure of amino acids, nitrogen is a key component of the chemical groups that allow these molecules to link together. For example, in the amino acid proline, the nitrogen atom is linked to two carbon atoms to form a cyclic structure. Because proteins are composed of chains of amino acids, the presence of nitrogen is necessary for the synthesis and structural integrity of these proteins, which perform a vast array of biological roles.21

Beyond proteins, nitrogen is also required to construct DNA and RNA, the molecules that carry genetic information. While nitrogen is abundant in the atmosphere, most organisms must obtain it through the nitrogen cycle after it has been converted into reactive compounds like ammonia or nitrates.1