Why is nitrogen essential to life?
Nitrogen is needed to make chemical compounds necessary for life.
DNA uses nitrogen bases as an essential part of its coding system. Without nitrogen it is impossible for the cell to make DNA. So the nitrogen fixing bacteria that pull nitrogen out of the atmosphere are in a way the basis for all other life.
RNA uses all but one of the same nitrogen bases. Some forms of life use RNA has it genetic material instead of DNA. Most forms of life use RNA to send messages from the DNA to the cells.
The most common message carried by the RNA is to make proteins.
All proteins have an acid end and an amnio end. The amino end is made of nitrogen. Without nitrogen the cells can not make the proteins essential for life.
Nitrogen is essential for making DNA, RNA, and proteins. These chemical are essential for life.