And this is the hydroxyl group that makes this molecule very, very slightly polar. So the predominant region of this cholesterol is in fact nonpolar. And this entire section will be found inside that membrane. But this tiny region will point to the aqueous environment and it will interact with the nearby heads of those phospholipid molecules because the heads consist of the phosphate groups and sometimes the alcohol molecules that contain those polar regions. So the hydroxyl group, being a polar region, basically interacts with the hydrophobic heads of the phospholipids in that cell membrane and therefore it points towards the aqueous environment. And the rest of the cholesterol molecule, the four fuse rings, as well as this hydrocarbon chain.