And so we see that if we use one NADH molecule, we basically transport a total of ten four, two and two. So ten H plus ions into the intermembrane space, and that establishes an electrochemical gradient. Now, that means we have many more H plus ions found on the intermembrane space than in the mitochondrial matrix. 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.