Cholesterol

Cholesterol, from the Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol, is an organic molecule. It is a sterol (or modified steroid),It is an essential structural component of all mammalian cell membranes that is required to establish proper membrane permeability and fluidity.
In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D. Cholesterol is the principal sterol synthesized by animals; in vertebrates it is formed predominantly in the liver. Small quantities are synthesized in other cellular organisms (eukaryotes) such as plants and fungi. It is almost completely absent among prokaryotes (i.e., bacteria).
François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769. However, it was only in 1815 that chemist Eugène Chevreul named the compound "cholesterine