The chemistry of living systems representing all chemical reactions is called

The chemistry of living systems representing all chemical reactions is called metabolism.

Metabolism is defined as a set of all chemical reactions within an organism. Purposes of metabolic processes are to convert food energy into energy that is required for cellular processes, to synthesize the building blocks for proteins, lipids, nucleic acids, and some carbohydrates (macromolecules) and to eliminate nitrogenous wastes. Catabolism and anabolism are part of the metabolism that work together in order to maintain functions within the cell.

Catabolic processes (breaking down of macromolecules) are necessary for energy release (usually in the form of ATP) which is then used in anabolism-synthesis of compounds that cell needs.