Carbohydrates are the most abundant organic compounds in living things. They are made up of carbon, hydrogen, and oxygen atoms. Carbohydrates are used for energy and storage of energy.
Proteins are made up of amino acids. They are used for building and repairing tissues, as well as for regulating chemical reactions in the body.
Lipids are made up of fatty acids. They are used for storing energy, insulating the body, and protecting organs.
Nucleic acids are made up of nucleotides. They are used for storing and transmitting genetic information.