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Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis

chemiosmosis가 oxidative phosphorylation의 두단계 중 하나 라고 생각하시면 됩니다

Definition으로 접근해서 차이점을 보자면..Oxidative phosphorylation is the metabolic pathway in which electrons are transferred from electron donors to electron acceptors in redox reactions; this series of reactions releases energy which is used to form ATP.

phosphorylation이 phosphate group을 transfer 하는 거자나요? ADP에 Pi 을 더함으로서 ATP를 만드는것도 phophorylation 의 일종인데, e-을 transfer 함으로써 ( oxidative) phosphorylation을 하는것을 " Oxidative phosphorylation" 이라고 합니다

반면

 Chemiosmosis is the movement of ions across a semipermeable membrane, down their electrochemical gradient. The process which use the energy stored in the proton gradient across the membrane to drive a cellular work is called chemiosmosis. An example of this would be the generation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H⁺) across a membrane during cellular respiration. 

electron을 transfer함으로써  만들어진 proton gradient 을 이용하여 ( 이 과정이 ETC) ,  proton 이 move down their elcetrochemical gradient through ATP synthase to make ATP ( 이 과정은 chemiosmosis) .  ETC 와 Chemiosmosis 가 합작하여 ATP 를 만들었네요. 이것을 Oxidative phosphorylation이라고 합니다.