An energy diagram for the transfer of electrons in the light reactions of photosynthesis in plants is

An energy diagram for the transfer of electrons in  the light reaction of photosynthesis in plants is Zscheme. Plastocyanin transfers electrons to ${\mathrm{P}}_{700}$ reaction centre of PS I. On getting excited, ${\mathrm{P}}_{700}$ hand over electrons to a special electron acceptor molecule, which passed downhill to energy rich molecule. This is called Z scheme due to its characteristic zig zag shape. This shape is formed when all the carriers are placed in a sequence on a redox potential scale.