Editing Metabolism (section)

==History==
{{further|History of biochemistry|History of molecular biology}}

The term ''metabolism'' is derived from the [[Ancient Greek]] word μεταβολή—"metabole" for "a change" which is derived from μεταβάλλειν—"metaballein", meaning "to change"<ref>{{Cite web|title=metabolism {{!}} Origin and meaning of metabolism by Online Etymology Dictionary|url=https://www.etymonline.com/word/metabolism|access-date=2020-07-23|website=www.etymonline.com|language=en|archive-date=21 September 2017|archive-url=https://web.archive.org/web/20170921001422/http://www.etymonline.com/index.php?term=metabolism|url-status=live}}</ref>

[[File:Aristotle's metabolism.png|thumb|right|upright=1.4|[[Aristotle's biology|Aristotle's metabolism]] as an open flow model]]

===Greek philosophy===
[[Aristotle]]'s ''[[The Parts of Animals]]'' sets out enough details of [[Aristotle's biology|his views on metabolism]] for an open flow model to be made. He believed that at each stage of the process, materials from food were transformed, with heat being released as the [[classical element]] of fire, and residual materials being excreted as urine, bile, or faeces.<ref>{{cite book|author=Leroi, Armand Marie|url=https://archive.org/stream/lagoonhowaristot0000lero?ref=ol#page/402/mode/2up|title=The Lagoon: How Aristotle Invented Science|date=2014|publisher=Bloomsbury|isbn=978-1-4088-3622-4|pages=400–401|author-link=Armand Marie Leroi}}</ref>

[[Ibn al-Nafis]] described metabolism in his 1260 AD work titled [[Al-Risalah al-Kamiliyyah fil Siera al-Nabawiyyah]] (The Treatise of Kamil on the Prophet's Biography) which included the following phrase "Both the body and its parts are in a continuous state of dissolution and nourishment, so they are inevitably undergoing permanent change."<ref>{{cite conference | vauthors = Al-Roubi AS | date = 1982 | title = Ibn Al-Nafis as a philosopher | conference = Symposium on Ibn al-Nafis, Second International Conference on Islamic Medicine | publisher = Islamic Medical Organization | location = Kuwait }}</ref>

===Application of the scientific method ===
The history of the scientific study of metabolism spans several centuries and has moved from examining whole animals in early studies, to examining individual metabolic reactions in modern biochemistry. The first controlled [[experiment]]s in human metabolism were published by [[Santorio Santorio]] in 1614 in his book ''Ars de statica medicina''. He described how he weighed himself before and after eating, [[sleeping|sleep]], working, sex, fasting, drinking, and excreting. He found that most of the food he took in was lost through what he called "[[insensible perspiration]]".<ref name=Sanctorius>{{cite journal | vauthors = Eknoyan G | title = Santorio Sanctorius (1561-1636) - founding father of metabolic balance studies | journal = American Journal of Nephrology | volume = 19 | issue = 2 | pages = 226–33 | year = 1999 | pmid = 10213823 | doi = 10.1159/000013455 | s2cid = 32900603 }}</ref>

[[File:SantoriosMeal.jpg|thumb|right|upright=0.7|[[Santorio Santorio]] in his steelyard balance, from ''Ars de statica medicina'', first published 1614]]

In these early studies, the mechanisms of these metabolic processes had not been identified and a [[vitalism|vital force]] was thought to animate living tissue.<ref>{{cite book|url=https://archive.org/details/historyofscience04willuoft/page/n7/mode/2up|title=Modern Development of the Chemical and Biological Sciences|vauthors=Williams HA|date=1904|publisher=Harper and Brothers|series=A History of Science: in Five Volumes|volume=IV|location=New York|pages=184–185|access-date=26 March 2007}}</ref> In the 19th century, when studying the [[fermentation (food)|fermentation]] of sugar to [[ethanol|alcohol]] by [[yeast]], [[Louis Pasteur]] concluded that fermentation was catalyzed by substances within the yeast cells he called "ferments". He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."<ref>{{cite journal | vauthors = Manchester KL | title = Louis Pasteur (1822-1895)--chance and the prepared mind | journal = Trends in Biotechnology | volume = 13 | issue = 12 | pages = 511–5 | date = December 1995 | pmid = 8595136 | doi = 10.1016/S0167-7799(00)89014-9 }}</ref> This discovery, along with the publication by [[Friedrich Wöhler]] in 1828 of a paper on the chemical synthesis of [[urea]], and is notable for being the first organic compound prepared from wholly inorganic precursors.<ref>{{cite journal | vauthors = Kinne-Saffran E, Kinne RK | title = Vitalism and synthesis of urea. From Friedrich Wöhler to Hans A. Krebs | journal = American Journal of Nephrology | volume = 19 | issue = 2 | pages = 290–4 | year = 1999 | pmid = 10213830 | doi = 10.1159/000013463 | s2cid = 71727190 }}</ref> Wöhler's urea synthesis showed that organic compounds could be created from inorganic precursors, disputing the vital force theory that dominated early 19th-century science. Modern analyses consider this achievement as foundational for unifying organic and inorganic chemistry.<ref>{{Cite journal |last=Kinne-Saffran |first=E. |last2=Kinne |first2=R. K. |date=1999 |title=Vitalism and synthesis of urea. From Friedrich Wöhler to Hans A. Krebs |url=https://pubmed.ncbi.nlm.nih.gov/10213830 |journal=American Journal of Nephrology |volume=19 |issue=2 |pages=290–294 |doi=10.1159/000013463 |issn=0250-8095 |pmid=10213830}}</ref>

It was the discovery of [[enzyme]]s at the beginning of the 20th century by [[Eduard Buchner]] that separated the study of the chemical reactions of metabolism from the biological study of cells, and marked the beginnings of [[biochemistry]].<ref>Eduard Buchner's 1907 [http://nobelprize.org/nobel_prizes/chemistry/laureates/1907/buchner-lecture.html Nobel lecture] {{Webarchive|url=https://web.archive.org/web/20170708144420/http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1907/buchner-lecture.html |date=8 July 2017 }} at http://nobelprize.org {{Webarchive|url=https://web.archive.org/web/20060405023917/http://nobelprize.org/ |date=5 April 2006 }} Accessed 20 March 2007</ref> The mass of biochemical knowledge grew rapidly throughout the early 20th century. One of the most prolific of these modern biochemists was [[Hans Adolf Krebs|Hans Krebs]] who made huge contributions to the study of metabolism.<ref>{{cite journal | vauthors = Kornberg H | title = Krebs and his trinity of cycles | journal = Nature Reviews. Molecular Cell Biology | volume = 1 | issue = 3 | pages = 225–8 | date = December 2000 | pmid = 11252898 | doi = 10.1038/35043073 | s2cid = 28092593 }}</ref> He discovered the urea cycle and later, working with [[Hans Kornberg]], the citric acid cycle and the glyoxylate cycle.<ref>{{cite journal |vauthors=Krebs HA, Henseleit K |title=Untersuchungen über die Harnstoffbildung im tierkorper |journal=Z. Physiol. Chem. |volume=210 |issue=1–2 |pages=33–66 |year=1932 |doi=10.1515/bchm2.1932.210.1-2.33}}</ref><ref>{{cite journal | vauthors = Krebs HA, Johnson WA | title = Metabolism of ketonic acids in animal tissues | journal = The Biochemical Journal | volume = 31 | issue = 4 | pages = 645–60 | date = April 1937 | pmid = 16746382 | pmc = 1266984 | doi = 10.1042/bj0310645 }}</ref><ref name="Kornberg-1957"/> Modern biochemical research has been greatly aided by the development of new techniques such as [[chromatography]], [[NMR spectroscopy]], [[electron microscope |electron microscopy]] and [[molecular dynamics]] simulations. These techniques have allowed the discovery and detailed analysis of the many molecules and metabolic pathways in cells.<ref name="x252">{{cite book | last=Das | first=Bidisha | last2=Chakraborty | first2=Joy | last3=Chattopadhyay | first3=Krishnananda | title=Biochemical and Biophysical Methods in Molecular and Cellular Biology | chapter=Emerging Techniques in Cellular and Biomolecular Research | publisher=Springer Nature Singapore | publication-place=Singapore | date=2025 | isbn=978-981--962087-6 | doi=10.1007/978-981-96-2088-3_1 | url=https://link.springer.com/10.1007/978-981-96-2088-3_1 | access-date=2025-04-17 | page=1–28}}</ref>