Cholesterol is a lipid found in the cell membranes of all tissues, and it is transported in the blood plasma of all animals. Cholesterol is also considered a sterol (a combination steroid and alcohol).
The name cholesterol originates from the Greek chole- (bile) and stereos (solid), and the chemical suffix -ol for an alcohol, as researchers first identified cholesterol in solid form in gallstones by François Poulletier de la Salle in 1769.
Most of the cholesterol in the body is synthesized by the body; some has dietary origin.
Cholesterol plays a central role in many biochemical processes, such as the composition of cell membranes and the synthesis of steroid hormones.
Cholesterol is insoluble in blood, but is transported in the circulatory system bound to one of the varieties of lipoprotein, spherical particle/s which have an exterior composed mainly of water-soluble proteins. The main types, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) carry cholesterol from and to the liver, respectively.
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