Which functional class do sterols belong to within lipids?

Sterols belong to the complex lipids functional class. Complex lipids are characterized by their structures that include not only fatty acids but also other groups, such as phosphates or sugars. Sterols specifically are a subgroup of complex lipids that feature a unique multi-ring structure, differing from the linear chains associated with simple lipids.

In contrast, simple lipids consist primarily of triglycerides, which are formed by glycerol and three fatty acids. Waxes are another type of lipid characterized by long-chain fatty acids esterified to long-chain alcohols, which do not include the sterol structure. Fatty acids themselves are the building blocks of many lipids and do not represent a class that includes sterols. As a result, identifying sterols as part of the complex lipids aligns with their structural complexity and functional role in biological systems.