In what ways is the inner mitochondrial membrane essential to the coupling of electron transport and ATP synthesis? Could the membrane carry out its function if its lipid bilayer were readily permeable to hydrogen ions (protons) ?

The inner mitochondrial membrane through its ATP pumps maintains a high concentration of protons between the two membranes, this builds up a charge difference and the movement of Hydrogen ions back in through gated cyclic pathways allows the generation of ATP which would not be possible if the membrane freely allowed protons back in.