e/P680

Information
has gloss	eng: P680, or Photosystem II primary donor, (where P stands for pigment) refers to any of the 2 special chlorophyll dimers (also named special pairs), PD1 or PD2 . These 2 special pairs form an excitonic dimer which means that they functionally behave as a single entity, i.e. they are excited as if they were a single molecule. The 680 number is its absorption maximum in the red part of the visible spectrum (680 nm). The primary donor receives excitation energy either by absorbing a photon of suitable frequency (colour) or by excitation energy transfer from other chlorophylls within photosystem II. During excitation an electron is excited to a higher energy level. This electron is subsequently captured by the primary electron acceptor, a pheophytin molecule located within photosystem II near P680. The oxidized P680 (P680+) is subsequently reduced by an electron originating from water (via Oxygen evolving complex).
lexicalization	eng: P680
instance of	c/Light reactions