The metabolism applies to the assembly of biochemical reaction which is employed by the organisms for the synthesis of cell material and for the utilization of energy from their environments. It may be defined as the sum total of all the enzyme-catalyzed reaction that occurs in an organism. A large number of reactions in a cell are organized into a relatively small number of sequence or pathways, it is a highly coordinated and purposeful selectivity in which multi-enzyme systems cooperate. This obviously points out to the fact that the metabolism of even or simple unicellular organism is time-variant. Metabolism in microorganisms and human beings.

The various processes of constituting metabolism may be divided somewhat arbitrary into catabolism and anabolism. Those processes for measure function is the generation of chemical energy in forms suitable for the mechanical and chemical processes of the cells are termed as catabolism whereas is those processes which utilize the energy generated by catabolism for the biosynthesis of cell components are termed as anabolism. The various activities powered by the catabolism include mechanical movement, growth, reproduction, accumulation of foods, elimination of waste, generation of electricity and maintenance of temperature, etc. & the various anabolism activities may be exemplified by the food manufacturer, etc.

Some processes can be either catabolic or anabolic depending on the energy condition in the cell.

Functions of Metabolism are: In all cells metabolism enables the cell to perform its vital functions. Metabolism performs the following four specific functions:

  • To obtain chemical energy from the degradation of energy-rich nutrient or from captured solar energy.

  • To convert nutrient molecules into precursors of cell macromolecules.

  • To assemble this free precursor into proteins, lipids, polysaccharides, nucleic acid, and other cell components.

  • To form and degrade biomolecules required in specialized function of cells.

Metabolism is closely interrelated since the synthesis of the molecule, that is a component of cell requires an input of energy, while at the same time it is obvious that our cell component is needed to provide the energy supply and to control intracellular solute concentration and the specialized function also requires biosynthetic process as well as a supply of energy. Terms catabolism (dissimulation) are synonyms and referred to the pathways or routes breaking down food material into simpler compounds and resulting in the release of energy contained in them & the process of anabolism (assimilation) utilize food materials and energy to synthesize cell components.