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 I Need What I Need "What I Need" is a song by American recording artist Ray J. It was written by Rodney "Darkchild" Jerkins, LaShawn Daniels, Fred Jerkins III, and Ray J for his 2005 album "Raydiation", while production was handled by the former. Released as the second single from the album following "One Wish", it reached number 58 on "Billboard"s Hot R&B/Hip-Hop Songs chart. "What I Need" earned generally positive reviews by critics. "Billboard" magazine felt that the song "should be enough to momentum. Here, Ray J's vocals once again seem strained as he cops another plea to the woman he