Redox-driven photosystem

In biological photosystems (whole cells, thylakoids or isolated PSI) a simple redox catalyst transfers electrons from the terminal acceptor of PSI to oxygen, the light-transducing system being the natural photosynthetic apparatus itself. In artificial model systems, by contrast, it is a redox photocatalyst (flavin or Ru (II)-tris(2, 2 -bipyridine)) who promotes the light-driven transfer of electrons from appropriate electron donors to molecular oxygen. 

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