What is a proton gradient’s role in the formation of ATP?

A proton gradient refers to a difference in proton concentration across a membrane. It is typically created during the electron transport chain in cellular respiration. The proton gradient plays a key role in the formation of ATP through a process known as chemiosmosis.

In chemiosmosis, protons (H+ ions) move across a membrane from an area of higher concentration to an area of lower concentration, facilitated by a protein complex called ATP synthase. This movement of protons is driven by the proton gradient, which is established across the inner mitochondrial membrane. 

As protons move down their concentration gradient to the side of the membrane with lower energy, ATP synthase harnesses the released energy to convert ADP into ATP.