Now, in eukaryotes, our cholesterol basically controls the cell and membrane fluidity. In prokaryotes, it's another type of molecule that also looks like cholesterol, but it's called a hopinoid. Both of these types of molecules basically function in the same exact way. So cholesterol is an extremely important component of the cell membrane. The polar hydroxyl groups of our cholesterol basically interact with the hydrophilic polar heads and the rest of the cholesterol molecule, which is basically a hydrocarbon backbone. The nonpolar region basically extends throughout the entire section of our cell membrane like this integral protein.