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823  Explain the light dependent reactions

Page history last edited by Jennifer Oh 10 years, 1 month ago


Go back to 3.8 assessment statements


In light dependent reactions, first light energy is converted into chemical energy. The light dependent reactions begin in Photosystem II, which is chlorophyll and the accessory pigments grouped together in large light-harvesting arrays, located in the thylakoids. The electron acceptor for this photosystem is called plastoquinone. At the center of the Photosystem are chlorophyll a, each of which is specialized to absorb a particular wavelength of light. It collects two excited electrons from Photosystem II and then moves away to another position in the membrane. Since plastoquinone is hydrophobic, though it is not in a fixed position it remains within the membrane. When two photons absorb light, the production of one reduced plastoquinone is caused, with one of the chlorophylls at the reaction center having lost two electrons. The chlorophyll passes excited electrons to a chain of electron carriers.



source: http://images-mediawiki-sites.thefullwiki.org/11/1/5/7/28989193854624099.png



Comments (1)

jeonelizabeth12@gsiscommunity.kr said

at 8:23 pm on Mar 16, 2011

Jennifer; I think your page will be much better if this paragraph is organized in bullet points since it is a very complex topic.
Also, you might want to add some "key words". The teacher's notes state to include "photoactivation of photosystem II" " photolysis of water" "electron transport" "cyclic and non-cyclic photophosphorylation" "photoactivation of photosystem I" and "reduction of NADP+".
Lastly, it will be very great to include some diagrams that clearly shows this complicated process. http://images-mediawiki-sites.thefullwiki.org/11/1/5/7/28989193854624099.png Yet, I cannot find a great clear diagram as well .... this image is the best I can find until now :(

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