Photosynthesis called P680. The source of electrons for photosynthesis in green plants and cyanobacteria is water. Two water molecules are oxidized by four successive charge-separation reactions by photosystem II to yield a molecule of diatomic oxygen and four hydrogen ions. The electrons yielded are transferred to a redox-active tyrosine residue that then reduces the oxidized P680. This resets the ability of P680 to absorb another photon and release another photo-dissociated electron. The oxidation of water is catalyzed in photosystem II by a redox-active structure that contains four manganese ions and a calcium ion; this oxygen-evolving complex binds two water molecules and
What More Do I Need? What More Do I Need? "What More Do I Need?" is the 94th episode of the ABC television series, "Desperate Housewives". It is the seventh episode of the show's fifth season and aired on November 9, 2008. The story continues from the previous episode, when Lynette confronted Tom after she thought he is having an affair. They both misunderstood each other, but the situation is immediately resolved when Lynette realizes that Porter is the one who is having sex with Anne. Lynette and Tom ask Porter to end the relationship via the phone, but Porter refuses, fearing that Mr. Schilling