Answer:
In ATP synthase, the alpha-beta subunits are arranged in a ring-shaped structure called the rotor. This rotor rotates as protons flow through it, and this rotation drives the synthesis of ATP.
Step-by-step explanation:
When one of the alpha-beta subunits binds ADP + inorganic phosphate and another alpha-beta subunit binds nothing, the third alpha-beta subunit binds the product of the ATP synthesis reaction, which is adenosine triphosphate (ATP). The binding of ATP to the third alpha-beta subunit causes a conformational change in the protein that releases the ATP from the enzyme complex, making it available for use as an energy source by the cell. So to summarize, the binding of ADP + inorganic phosphate to one alpha-beta subunit and the absence of binding to another alpha-beta subunit creates a binding site for ATP on the third alpha-beta subunit of the ATP synthase complex.