The term "anabolic" refers to those biochemical processes in the body which require energy and/or store energy. Anabolic reactions build new and more complex molecules from simpler ones. This is a process which requires energy, but also stores energy in the newly created and larger molecule.
Catabolic processes represent the inverse reaction. They will release energy as larger molecules are broken down into smaller ones. The energy released by catabolic reactions will provide the energy for further anabolic reactions. The energy used to fuel anabolic reactions is stored in ATP, the shorter term for adenosine triphosphate, the coenzyme responsible for the transfer of intercellular energy.
When ATP breaks down into a smaller molecule called ADP, or adenosine diphosphate, it loses one of its three phosphates and releases energy in a catabolic reaction. In the anabolic version, ADP gains a third phosphate and stores energy as it transforms into the larger ATP. This repeating cycle of energy storage and release is referred to as an organism's metabolism, a term which also represents the totality of all the biochemical reactions occurring within an organism. The series of reactions in which one leads into the next are called metabolic pathways.
The anabolic processes help to build up tissues and organs, which also aids in the growth of the organism through increases in muscle mass and the mineralization of bones. Endocrinologists often refer to various hormones as either anabolic or catabolic, depending on which portion of the organism's metabolism they affect.