# The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because :

(1) there is a change in the permeability of the inner mitochondrial membrane toward adenosine diphosphate (ADP)

(2) high energy bonds are formed in mitochondrial proteins

(3) ADP is pumped out of the matrix into the intermembrane space

(4) a proton gradient forms across the inner membrane