ABSTRACT
Metabolism can be defined as the sum of the chemical changes that occur in the cell and involve the breakdown and synthesis of stored energy sources. Metabolism can be divided into two basic processes: (1) anabolism, involving the synthesis of cellular macromolecules, and (2) catabolism, the breakdown of energy stores to adenosine triphosphate (ATP) and reducing equivalents for cell function and provision of precursors for anabolism. The balance between the anabolic and catabolic processes is by the actions of hormones, which coordinate and control tissue responses. Acute control of these processes is via hormones that rapidly modify the activity of existing enzymes, whilst chronic control is effected by the amount of enzymes in the cells.
