So we have the hydrophilic regions of the proteins, this region here and this region here. And the rest of the protein found inside is hydrophobic. It's nonpolar, so it interacts with these hydrophobic nonpolar tails, our fatty acids. So, anterioral proteins extend throughout the entire bilayer membrane. And their usual function, because they extend through the entire membrane, is to transport things from the inner portion to the outer portion of our cell. So basically to the outside, or vice versa, from the outside to our inside.