So number seven, which is what we mentioned earlier and just a moment ago, membranes are polar. And what that means is, compared to the outside of the cell, the inside of the cell basically differs in the charge. And because we have a separation of charge between the two sides of the membrane, from basic physics, we know that that creates establishes an electric potential difference, an electric dipole moment. So there is a dipole moment that exists between the two sides will have electric field, an electric field that will exist within this region and that will basically store energy within that region. It will give the membrane a voltage difference. And number eight, membranes are not symmetric structures.