sterol

n. any of a group of alcohols of the steroid group (Chemistry)

Sterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring. They are amphipathic lipids synthetised from acetyl-coenzyme A. The overall molecule is quite flat. The hydroxyl group on the A ring is polar. The rest of the aliphatic chain is non-polar.Sterols of plants are called phytosterols and sterols of animals are called zoosterols. The most important zoosterols are cholesterol and some steroid hormones; the most important phytosterols are campesterol, sitosterol, and stigmasterol.Sterols play essential roles in the physiology of eukaryotic organisms. For example cholesterol forms part of the cellular membrane where its presence decreases the cell membrane's fluidity and serves as secondary messenger in developmental signaling.
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Sterol /ster·ol/ any of a group of steroids with a long aliphatic side-chain at position 17 and at least one alcoholic group; they have lipidlike [more]Sterol - Community and Resources

Noun
1. any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances
(synonym) steroid alcohol
(hypernym) alcohol
(hyponym) cholesterol, cholesterin

sterol