<P> This initial charge separation occurs in less than 10 picoseconds (10 seconds). In their high - energy states, the special pigment and the acceptor could undergo charge recombination; that is, the electron on the acceptor could move back to neutralize the positive charge on the special pair . Its return to the special pair would waste a valuable high - energy electron and simply convert the absorbed light energy into heat . In the case of PSII, this backflow of electrons can produce reactive oxygen species leading to photoinhibition . Three factors in the structure of the reaction center work together to suppress charge recombination nearly completely . </P> <Ul> <Li> Another electron acceptor is less than 10 Å away from the first acceptor, and so the electron is rapidly transferred farther away from the special pair . </Li> <Li> An electron donor is less than 10 Å away from the special pair, and so the positive charge is neutralized by the transfer of another electron </Li> <Li> The electron transfer back from the electron acceptor to the positively charged special pair is especially slow . The rate of an electron transfer reaction increases with its thermodynamic favorability up to a point and then decreases . The back transfer is so favourable that it takes place in the inverted region where electron - transfer rates become slower . </Li> </Ul> <Li> Another electron acceptor is less than 10 Å away from the first acceptor, and so the electron is rapidly transferred farther away from the special pair . </Li> <Li> An electron donor is less than 10 Å away from the special pair, and so the positive charge is neutralized by the transfer of another electron </Li>

Where is atp synthesized in the light reactions