Science, Tech, Math › Science Metabolism Definition in Science What Does Metabolism Mean in Science? Share Flipboard Email Print Metabolism refers to the set of biochemical reactions that occur in a cell or organism. Yagi Studio / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated December 07, 2019 Metabolism is the set of biochemical reactions involved in storing fuel molecules and converting fuel molecules into energy. Metabolism may also refer to the sequence of biochemical reactions compounds undergo inside a living cell. The word "metabolism" comes from the Greek word metabolē, which means "change." Anabolism and Catabolism Metabolism or metabolic reactions include anabolic reactions and catabolic reactions. Anabolic reactions synthesize or build compounds, such as proteins, nucleic acids, carbohydrates, and lipids. Catabolic reactions break down complex molecules into simpler ones, often releasing energy in the process. A good example of a catabolic reaction is the breakdown of glucose into pyruvate by cellular respiration. Functions of Metabolism Metabolism serves three key functions: It converts food into the energy required to run the cell and the body.It converts food into building blocks used to make molecules the cell and body need.It eliminates nitrogenous wastes. History The study of metabolism dates back at least to the time of the ancient Greeks. Aristotle's The Parts of Animals described the process of transforming food into usable materials, the release of heat as food was used, and the excretion of urine and feces. In 1260 AD, Ibn al-Nafis described the constant building and dissolution within the body in his work Al-Risalah al-Kaniliyyah fil Siera al-Nabawiyyah (The Treatise of Kamil on the Prophet's Biography). Santorio Santorio conducted controlled experiments on metabolism in 1614, which he outlined in his book Ars de statica medicina. The chemical mechanisms of metabolism weren't really understood until the 19th century, while the structures of the molecules weren't known until the 20th century. Sources Berg, J.; Tymoczko, J.; Stryer, L. (2002). Biochemistry. W. H. Freeman and Company. ISBN 0-7167-4955-6.Rose, S.; Mileusnic, R. (1999). The Chemistry of Life. Penguin Press Science. ISBN 0-14-027273-9.