The polar portion of a cholesterol molecule, which forms hydrogen bonds with the polar heads of neighboring phospholipids and glycolipids, consists of a hydroxyl group or -OH. From the name of the molecule, you can easily say that it should contain an hydroxyl group as it has an -ol in its name. Alcohol is a polar molecule so this part of cholesterol should be the polar portion. Cholesterol is a modified steroid and a lipid molecule. It is an important structural molecule of all cell membranes, maintaining fluidity and structural integrity. It is also a starting material for the synthesis of bile acid, vitamin D and steroid.