Cholesterol
= Cholesterol
<Cholesterol> is a <lipid> with four fused rings and a small <hydrophilic> region. It helps regulate the fluidity of animal <cell membranes>; it is structurally distinct from a <phospholipid>. See https://openstax.org/books/biology-2e/pages/3-3-lipids[Biology 2e: cholesterol].