C. electron transport and chemiosmosis
Chemiosmosis involves movement of ions across a semipermeable membrane, down their electrochemical gradient. More specifically, it relates to the generation of adenosine triphosphate (ATP) by the movement of hydrogen ions across a membrane during cellular during respiration .Hydrogen ions, or protons, will diffuse from an area of high proton concentration to an area of lower proton concentration, and an electrochemical concentration gradient of protons across a membrane can be harnessed to make ATP. This process is related to osmosis, the diffusion of water across a membrane, which is why it is called "chemiosmosis".