Final answer:
Nitrogen is essential to life as it forms amino acids for proteins, nucleic acids for DNA, and is made available to organisms through the process of nitrogen fixation.
Step-by-step explanation:
Nitrogen is important to all living things for several reasons, but three key functions include:
- Nitrogen is a part of amino acids, which help build proteins.
- It is a part of nucleic acids, which help build DNA.
- Nitrogen fixation is a vital process for converting nitrogen from the atmosphere into a form that organisms can use to build these essential molecules.
While nitrogen accounts for about 50% of the total composition of a cell, proteins, as nitrogenous organic compounds, play a vital role in organisms and are composed of amino acids. Furthermore, nucleic acids like DNA contain nitrogen as a fundamental component. Due to the strong triple bond in nitrogen gas (N₂), most organisms cannot directly use atmospheric nitrogen; this is why nitrogen fixation is a critical step in the nitrogen cycle, allowing organisms to access nitrogen in a usable form.