Editing Electron transport chain (section)

==Photosynthetic==
{{Further|Light-dependent reaction|Photosynthetic reaction center}}
[[File:Innerworkings of a thylakoid.png|thumb|Photosynthetic electron transport chain of the [[thylakoid membrane]].]]
In [[oxidative phosphorylation]], electrons are transferred from an electron donor such as NADH to an acceptor such as O{{sub|2}} through an electron transport chain, releasing energy. In [[photophosphorylation]], the energy of [[sunlight]] is used to create a high-energy electron donor which can subsequently reduce oxidized components and couple to ATP synthesis via proton translocation by the electron transport chain.<ref name=":1" />

Photosynthetic electron transport chains, like the mitochondrial chain, can be considered as a special case of the bacterial systems. They use mobile, lipid-soluble quinone carriers ([[phylloquinone]] and [[plastoquinone]]) and mobile, water-soluble carriers ([[cytochrome]]s). They also contain a [[proton pump]]. The proton pump in ''all'' photosynthetic chains resembles mitochondrial ''Complex III''. The commonly-held theory of [[symbiogenesis]] proposes that both organelles descended from bacteria.