Now, this complex is actually a very large complex. In fact, it consists of about 46 individual polypeptide chains. And if we examine the shape of protein complex one, we'll notice that it looks like the letter L. So the letter L, which basically looks like this, contains a horizontal component and a vertical component. Now, the vertical component is basically exposed to the matrix of the mitochondria. But the horizontal component, this component, lies entirely in the membrane, the inner membrane of the mitochondria. So the entire function of protein complex One is to accept those high energy electrons from NADH molecules and to move those electrons along a special pathway within the complex that we're going to focus on in detail in electra to come.