The four main classes of biomolecules are proteins, carbohydrates, lipids, and nucleic acids. Proteins are some of the most diverse biomolecules, and they can perform functions such as protecting the body from pathogens or acting as catalysts for chemical reactions. Carbohydrates can be a source of energy when your body needs it. Lipids include fat molecules and are used for energy storage as well as to form the membranes that surround each cell. Nucleic acids are what make up our genetic material and store the information that determines a lot about who we are. We’ll go into more details about each of these types of biomolecules in the upcoming pages.