And these two monomers are not attached by any type of bond so they're actually separated. And as we'll see in just a moment they actually dimerize. They form a dimer only upon the binding of the EGF molecule. Now let's examine each one of these individual monomers. So we have this purple region found on the extracellular side and this is a region that contains a binding side for that EGF molecule. This brown section is that section that essentially spans the membrane and it anchors that molecule in that membrane.