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
Ghetto Day/What I Need "What I Need" and "100% Pure Love", the album's first single, "ooze with giddy abandon—not to mention juicy grooves that seep deeper into the brain and body upon repeated spins." "What I Need" was claimed by "Spin" Bernstein to have "xeroxed" Clivillés and Cole's 1991 single "A Deeper Love". However, he predicted that it could have been a potential successor to her previous signature hits, "Gypsy Woman" and "Makin' Happy". "Ghetto Day" and "What I Need" were released as a double A-side single in June 1994. The joint release peaked at 40 on the UK Singles Chart and at No.