Chemiosmosis requires

a) proton pump                                                  

b) proton gradient

 c) selectively permeable membrane               

 d) ATP synthase

Chemiosmosis is a process that occurs in the inner mitochondrial membrane during cellular respiration and in the thylakoid membrane during photosynthesis. It involves the movement of protons (H⁺) across the membrane, creating a proton gradient. This gradient serves as a source of potential energy. The enzyme ATP synthase, which spans the membrane, utilizes this proton gradient to produce ATP (adenosine triphosphate) from ADP (adenosine diphosphate) and inorganic phosphate (Pi).