<unk> s are a class of lipids, and a major component of all biological membranes, along with glycolipids, cholesterol and proteins.  Understanding of the aggregation properties of these molecules is known as lipid polymorphism and forms part of current academic research.
Phospholipid
Glycolipid
Glycerophospholipid
Polyphosphate
Diatomic molecule
Nucleoside
Monosaccharide
Capsid