carbon
The cell is the basic unit of life. A cell is made of molecules, which are made of elements. All life-which means all bacteria and archaea, all protists, fungi, plants and animals-is built around the element carbon, and four categories of organic compounds: carbohydrates, lipids, proteins, and nucleic acids. These molecules come together to form a cell, which is the basis of life. One particular type of protein, enzymes, are biological catalysts, allowing biochemical reactions to proceed at the rate necessary to maintain life. One other molecule, water, is also essential to life, though water is not an organic compound.