What Is Nitrogen Used for in Animals & Plants?

Just like its neighbors carbon and oxygen on the periodic table, nitrogen is essential to life as we know it. Nitrogen's key role is as a component of two classes of vital molecules found in cells.

Types

• DNA and RNA are polymers formed from chains of subunits called nucleotides, while proteins are polymers formed from chains of amino acids. Proteins and nucleic acids both contain nitrogen and are fundamental to the nature of life on Earth.

Function

• The basic structure of an amino acid includes an amine group (-NH2) on one end and a carboxyl group (-COOH) on the other; the two are linked by a carbon atom. The carbon atom is bonded to a side chain. Amino acids differ in their side chains. Since all amino acids include nitrogen, nitrogen is necessary to synthesize amino acids. Nucleotides in DNA or RNA are composed of a sugar and phosphate group bonded to a nitrogen-containing base; consequently, nitrogen is necessary to synthesize DNA and RNA as well.

Considerations

• Neither animals nor plants can use atmospheric nitrogen -- it's inert and very nonreactive. Nitrogen fixation by bacteria or lightning converts atmospheric nitrogen into ammonia and nitrates, which plants can use. Animals obtain the nitrogen they need from amino acids in the proteins they consume when they eat plants or other animals.