What type of ion is built into a gradient so ATP synthase can work

hydrogen

hydrogen ion

Explanation:

ATP synthase is an enzyme that primarily participates in the respiratory chain, because its main function is to enable the formation of ATP (high energy molecule, necessary for almost all metabolic processes).

This approach uses a hydrogen ion gradient to function and produce ATP when needed. That's because this ion gradient is what generates energy for the enzyme. When the hydrogen ion gradient is large enough to provide the necessary energy, ATP synthase begins to bond with the substrate and catalyze the ATP production reaction.