So let's take this potassium ion and let's create a concentration cell or a specialized concentration cell called a neuron cell. So this is our electrochemical concentration cell for potassium. This is our negatively charged anode and our positively charged cathode. Now, this is where oxidation of potassium takes place. And this is where reduction of potassium takes place. You could think of this conductor, that electrodes and a sulfbridge, as representing the cell membrane.