Thursday, July 18, 2013

Cholesterol



Identifiers
CAS number 57-88-5 Yes
PubChem 5997
ChemSpider 5775 Yes
UNII 97C5T2UQ7J Yes
KEGG D00040 Yes
ChEBI CHEBI:16113 Yes
ChEMBL CHEMBL112570 Yes
Jmol-3D images Image 1
Properties
Molecular formula C27H46O
Molar mass 386.65 g/mol
Appearance white crystalline powder[2]
Density 1.052 g/cm3
Melting point 148–150 °C[2]
Boiling point 360 °C (decomposes)
Solubility in water 0.095 mg/L (30 °C)
Solubility soluble in acetone, benzene, chloroform, ethanol, ether, hexane, isopropyl myristate, methanol
Hazards
Flash point 209.3 ±12.4°C [1]
 Yes (verify) (what is: Yes/?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Cholesterol, from the Ancient 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),[3] and an essential structural component of animal cell membranes that is required to establish proper membrane permeability and fluidity. Cholesterol is thus considered within the class of lipid molecules.
In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D.[4] Cholesterol is the principal sterol synthesized by animals; in vertebrates it is formed predominantly in the liver. It is almost completely absent among prokaryotes (i.e., bacteria), although there are some exceptions such as Mycoplasma, which require cholesterol for growth[citation needed].
François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769. However, it was not until 1815 that chemist Michel Eugène Chevreul named the compound "cholesterine".