Electron Transport Chain of Chloroplast

Once water photolysis has supplied electrons to PS II, those electrons - and the electrons PS I separately releases on absorbing light - travel through a defined sequence of four functional complexes embedded in the thylakoid membrane, collectively called the electron transport chain. The core complex (CC) of each photosystem houses its reaction centre: CC I holds P700 (in PS I) and CC II holds P680 (in PS II). The light-harvesting or antenna complex (LHC) surrounds each core complex and comes in two matching types, LHC I (paired with PS I) and LHC II (paired with PS II), whose job is purely to funnel captured light energy inward. The cytochrome b6-f complex is a non-pigmented protein complex that physically bridges PS II and PS I, and it does not work alone: plastoquinone (PQ), a small mobile lipid-soluble carrier, shuttles electrons from PS II across to the cytochrome b6-f complex, while plastocyanin (PC), a small mobile water-soluble carrier, shuttles electrons onward from the cytochrome b6-f complex to PS I. Finally, the ATPase complex (also called the coupling factor) sits on the surface of the thylakoid membrane and is built from two linked sub-complexes, CF1 and CF0; it uses the energy released as electrons flow through the earlier steps of the chain - specifically, the proton gradient this flow builds up (detailed under the chemiosmotic theo …