MoBio Cholesterol and Steroids Chapter 1

Cholesterol is absent from most prokaryotic cells, but abundant in the plasma membrane of mammalian cells. It is used as a precursor to generate other important steroids.

Cholesterol plays a central role in atherosclerosis - a disorder that may cause heart attack or stroke. It is also involved in Alzheimer's disease.

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Figure 1-B-3. Structures of cholesterol and other important steroids. They are characterized by four hydrocarbon rings, designated as A, B, C, and D. Although cholesterol is made up of almost entirely hydrocarbons, it is still an amphipathic molecule (with both hydrophilic and hydrophobic parts) because it contains a hydroxyl group (OH).