Editing Chemical reaction (section)

==Biochemical reactions==
[[File:Induced fit diagram.svg|thumb|left|380px|Illustration of the induced fit model of enzyme activity]]
[[Biochemistry|Biochemical reactions]] are mainly controlled by complex [[protein]]s called [[enzymes]], which are usually specialized to [[Catalysis|catalyze]] only a single, specific reaction. The reaction takes place in the [[active site]], a small part of the enzyme which is usually found in a cleft or pocket lined by [[amino acid]] residues, and the rest of the enzyme is used mainly for stabilization. The catalytic action of enzymes relies on several mechanisms including the molecular shape ("induced fit"), bond strain, proximity and orientation of molecules relative to the enzyme, proton donation or withdrawal (acid/base catalysis), electrostatic interactions and many others.<ref>{{cite book | author = Karlson, Peter | author2 = Doenecke, Detlef | author3 = Koolman, Jan | author4 = Fuchs, Georg | author5 = Gerok, Wolfgang | title = Karlson Biochemistry and Pathobiochemistry | edition = 16th | url = https://books.google.com/books?id=8Eu_Hy8aVzMC&pg=PP1| language = de | publisher = [[Thieme Medical Publishers|Thieme]] | year = 2005 | isbn = 978-3-13-357815-8 | pages = 55–56}}</ref>

The biochemical reactions that occur in living organisms are collectively known as [[metabolism]]. Among the most important of its mechanisms is the [[anabolism]], in which different [[DNA]] and enzyme-controlled processes result in the production of large molecules such as [[protein]]s and [[carbohydrates]] from smaller units.<ref>{{GoldBookRef|title=anabolism|file=A00314}}</ref> [[Bioenergetics]] studies the sources of energy for such reactions. Important energy sources are [[glucose]] and [[Dioxygen in biological reactions|oxygen]], which can be produced by plants via [[photosynthesis]] or assimilated from food and air, respectively. All organisms use this energy to produce [[adenosine triphosphate]] (ATP), which can then be used to energize other reactions. Decomposition of organic material by [[Fungus|fungi]], [[bacteria]] and other [[Microorganism|micro-organisms]] is also within the scope of [[biochemistry]].