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
Liquid latex The fumes from the ammonia in liquid latex can irritate the eyes when used as special effect make up on the face. For this reason it is recommended that liquid latex be allowed to vent for several minutes before being applied in this way. Appropriate liquid latex safety guidelines should be followed before the cosmetic use of liquid latex. Latex is a natural ingredient that comes from rubber trees in the form of a milky liquid. There are thousands of species of plants that produce different types of latex, including the Chicle tree that yields the raw material for producing