Sterols are the organic compounds composed of the four rings fused together, an attached hydrocarbon chain and the characteristic functional group called -OH group attached to the ring.
The steroids are the compounds which contain the fused rings (a feature of sterol) and the attached -OH group. The presence of the hydrophobic chain provide makes them insoluble in water which is considered a characteristic feature of the lipids. Therefore the steroids are considered the lipid molecule or fatty acid-containing molecules.
The cholesterol is the most common type of sterol present in the organism, especially in the animal and plants.
