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 Ghetto Day/What I Need "Ghetto Day"/"What I Need" is the second single from American singer-songwriter Crystal Waters' second studio album, "Storyteller" (1994). It was produced by The Basement Boys and released in June 1994 by Mercury Records, A&M Records and A&M's division AM PM. Waters and Sean Spencer wrote "Ghetto Day", which is a funk song that contains samples from The 5th Dimension's song "Stoned Soul Picnic" and Flavor Unit's "Flavor Unit Assassination Squad". According to "Spin", the track's lyrics talk about "those balmy, front-stoop, 40-swinging summer afternoons." The single's second A-side, "What I Need", is a house track written