They attach that entire structure of the protein into that hydrophobic core of the membrane. And so four of these identical polypeptide chains come together to form a tetrimer structure that looks like a cone. And that's because on one side of that cone we have a larger opening than on the opposing side of that protein. Now we'll see why that's important. In just a moment. The first question that I basically want to ask is the following what exactly is it about this ion channel that gives it the property we call ion specificity?