Metabolic

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Metabolism refers to the set of life-sustaining chemical reactions that occur within living organisms. The word metabolism can also refer to all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells. In a broader sense, the set of reactions occurring within the cells is called intermediary metabolism. These enzyme-catalyzed reactions allow organisms to grow, reproduce, maintain their structures, and respond to their environments. The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical. Metabolism involves a vast array of chemical reactions, but most fall under a few basic types of reactions that involve the transfer of functional groups of atoms and their bonds within molecules.

Key facts

The three main functions of metabolism are the conversion of energy in food into a usable form for cellular processes, the conversion of food to building blocks of macromolecules, and the excretion of metabolic wastes. Metabolic reactions may be categorized as catabolic, the breaking down of compounds, or anabolic, the building up of compounds. Usually, catabolism releases energy, and anabolism consumes energy. Enzymes are crucial to metabolism because they allow organisms to drive reactions that require energy and will not occur by themselves. The metabolic system of a particular organism determines which substances it will find nutritious and which poisonous. The basal metabolic rate of an organism is the measure of the amount of energy consumed by all of these chemical reactions. A notable feature of metabolism is the similarity of the basic metabolic pathways among vastly different species. Most structures are made from four basic classes of molecules: amino acids, carbohydrates, nucleic acid and lipids. One central coenzyme is adenosine triphosphate which is the energy currency of cells.

When to seek professional help

The source text associates professional care with situations where normal metabolism is disrupted by various diseases. It specifies that in various diseases, such as type II diabetes, metabolic syndrome, and cancer, normal metabolism is disrupted. The metabolism of cancer cells is also different from the metabolism of normal cells. The source indicates these differences can be used to find targets for therapeutic intervention in cancer.

Source: Metabolism (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-08-27.