carbon
2.3 | Biological Molecules By the end of this section, you will be able to: Describe the ways in which carbon is critical to life Explain the impact of slight changes in amino acids on organisms Describe the four major types of biological molecules Understand the functions of the four major types of molecules The large molecules necessary for life that are built from smaller organic molecules are called biological macromolecules. There are four major classes of biological macromolecules carbohydrates, lipids, proteins, and nucleic acids , and each is an important component of the cell and performs a wide array of functions. Combined, these molecules make up the majority of a cells mass. Biological macromolecules are organic, meaning that they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, phosphorus, sulfur, and additional minor elements.