Oxidative phosphorylation and photophosphorylation are mechanistically similar Both involve the flow of electrons through a chain of membrane bound carriers The energy released from"downhill electron flow is first used for uphill" pumping of protons to produce a proton gradient(thus a transmembrane electrochemical potential) across a biomembrane aTP is then synthesized by a downhill transmembrane flow of protons through a specific protein machinery (ATP synthase)• Oxidative phosphorylation and photophosphorylation are mechanistically similar: – Both involve the flow of electrons through a chain of membrane￾bound carriers. – The energy released from “downhill” electron flow is first used for “uphill” pumping of protons to produce a proton gradient （thus a transmembrane electrochemical potential) across a biomembrane. – ATP is then synthesized by a “downhill” transmembrane flow of protons through a specific protein machinery (ATP synthase)