And so that means our H plus ions will naturally and spontaneously want to flow from the intermembrane space to the mitochondrial matrix. However, because they have a positive charge, they're polar. And that means they cannot actually pass through our phospholipid bilayer because of the hydrophobic tails. And that's exactly where ATP synthase comes into play. So ATP synthase is basically a complex of proteins that create channels that allow the H plus ions to flow through these regions. So basically, our H plus ions begin to travel down their electrochemical gradient from a high concentration to a low concentration from a lot of charge to a very little charge.