Editing Photosystem I (section)

=== Antenna complex ===

The antenna complex is composed of molecules of [[chlorophyll]] and [[carotenoid]]s mounted on two proteins.<ref name="Taiz">{{cite book |last1=Zeiger |first1=Eduardo |last2=Taiz |first2=Lincoln |name-list-style=vanc |chapter=Ch. 7: Topic 7.8: Photosystem I |chapter-url=http://4e.plantphys.net/article.php?ch=3&id=73 |title=Plant Physiology |publisher=Sinauer Associates |location=Sunderland, MA |year=2006 |isbn=0-87893-856-7 |edition=4th }}{{Dead link|date=April 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> These pigment molecules transmit the [[Förster resonance energy transfer|resonance energy]] from photons when they become photoexcited. Antenna molecules can absorb all [[wavelength]]s of light within the [[visible spectrum]].<ref name="kent">{{cite web |title=The Photosynthetic Process |url=http://kentsimmons.uwinnipeg.ca/cm1504/lightreact.htm |url-status=dead |archive-url=https://web.archive.org/web/20090219143934/http://kentsimmons.uwinnipeg.ca/cm1504/lightreact.htm |archive-date=2009-02-19 }}</ref> The number of these pigment molecules varies from organism to organism. For instance, the [[cyanobacteria|cyanobacterium]] ''Synechococcus elongatus'' (''Thermosynechococcus elongatus'') has about 100 chlorophylls and 20 carotenoids, whereas [[spinach]] chloroplasts have around 200 chlorophylls and 50 carotenoids.<ref name="kent"/><ref name="Nelson_2006"/> Located within the antenna complex of PSI are molecules of chlorophyll called [[P700]] reaction centers. The energy passed around by antenna molecules is directed to the reaction center. There may be as many as 120 or as few as 25 chlorophyll molecules per P700.<ref name="Shubin">{{cite journal | vauthors = Shubin VV, Karapetyan NV, Krasnovsky AA | title = Molecular arrangement of pigment-protein complex of photosystem 1 | journal = Photosynthesis Research | volume = 9 | issue = 1–2 | pages = 3–12 | date = January 1986 | pmid = 24442279 | doi = 10.1007/BF00029726 | bibcode = 1986PhoRe...9....3S | s2cid = 26158482 }}</ref>