Difference between Metabolism, Catabolism and Anabolism

Key Difference: Metabolism refers to the bio-chemical reactions that take place in an organism. These reactions are important for maintaining life. It consists of two processes – Catabolism and Anabolism. Catabolism deals with breakdown of larger molecules into smaller ones. These are usually energy releasing processes. On the other hand, Anabolism is related to the synthesis of complex molecules from simpler ones. These are energy-using processes.

Cells are important constituents of any organism. Numerous chemical reactions take place in these cells in order to carry out different actions. All the reactions are together referred to as metabolism. The chemicals that are involved in metabolism are known as metabolites. Metabolism as biochemical processes, are important in many contexts. They are important for maintaining life. These processes provide the necessary mechanisms for growth, reproduction, repair damage and many more.

The reaction of metabolism are organized into metabolic pathways like in a metabolic pathway known as glycolysis, glucose is converted into pyruvate and produce ATP. During the chemical reactions, energy is involved. It is either taken in or released. Metabolism is responsible for managing material and energy resources of the cell. In catabolism more complex organic molecules break down into simpler substances. These reactions usually result in release of energy which is further used to drive chemical reactions.

Example of Catabolism

Fuels (carbohydrates, fats, proteins) -> CO2 +H2O + useful energy

Organisms are classified on the basis of type of Catabolism –

Organotrophs - Organisms which use organic sources as a source of energy
Lithotrophs - Organisms which use inorganic substrates
Phototrophs – Organisms which use sunlight as chemical energy

On the other hand, in anabolism reactions, simpler substances combine to form complex molecules. These reactions generally require energy to take place. In this context, anabolism and catabolism can be considered as just opposite of each other. Thus, anabolism can be referred to as ‘building up’, whereas catabolism can be referred to as ‘breaking down’. The energy released by catabolic reactions is used for carrying out anabolic reactions.

Example of Anabolism

Useful energy + small molecules ->complex molecules

Metabolism comprises of both catabolism and metabolism. In this way, it balances both the activities that take place simultaneously. Catabolism is also known as destructive metabolism. On the other hand, anabolism is also known as constructive metabolism.

Comparison between Metabolism, Catabolism and Anabolism:

	Metabolism	Catabolism	Anabolism
Definition	Metabolism refers to the bio-chemical reactions that take place in an organism. It consists of two processes – Catabolism and Anabolism	Catabolism deals with energy releasing processes.	Anabolism is related to energy-using processes.
Origin of Word	From Greek: μεταβολή metabolē, "change" or Greek: μεταβολισμός metabolismos, "outthrow"	From Greek kata = downward + ballein = to throw	From Greek: ανά "upward" and βάλλειν "to throw"
Type	Includes catabolism and anabolism	It breaks things and releases energy	It builds things and consumes energy
Importance	Growth and division Maintaining cellular structures Sense/respond to environment	The energy released provides fuel for anabolism, heats the body, and enables the muscles to contract and the body to move.	It supports growth of new cells It helps in maintenance of body tissues It supports the storage of energy for future use
Energy Form	Includes enegy forms of catabolism and metabolism	Energy is released as kinetic energy	Energy is used and stored as potential energy
Example	Includes examples of catabolism and anabolism	Cell Respiration, Digestion, Excretion	Photosynthesis in plants, assimilation in animals