# Sterols --- **Sterols** are a type of [[lipids]] that regulates biological processes. ## Structure Sterols all have a common four ring structure. ![[sterol.png]] ## Cholesterol **[[Cholesterol]]** is a ubiquitous sterol in your body. It likes to live in biological membranes becaue it is fatty, and it's presence can decrease the permiability of a membrane by shoring up the gaps left by kinks in the fatty acids. As important as it is, too much of it in the wrong places can lead to an increased risk of cardiovascular disease. ### Steroid Hormones Colesterol is an important sterol, because, amung other things, it turns into all the "steroid [[hormone|hormones]]"", sometimes only differentiated by one atom, despite their vastly different functions. Estrogen, testosterone, progesterone, corticosteriods, and all steroid hormones. They have very subtle differences in their side chains. ![[sterol hormones.png]] ___