Metabolism is a term that is used to describe all chemical reactions involved in maintaining the living state of the cells and the organism. Metabolism can be conveniently divided into two categories:Catabolism - the breakdown of molecules to obtain energyAnabolism - the synthesis of all compounds needed by the cellsMetabolism is closely linked to nutrition and the availability of nutrients. Bioenergetics is a term that describes the biochemical or metabolic pathways by which the cell ultimately obtains energy. Energy formation is one of the vital components of metabolism.