Sterol

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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 cholesterol or zoosterol. The most important sterols are cholesterol, phytosterol, and some steroid hormones in animals, campesterol, and sitosterol, and stigmasterol in plants.

Sterols play essential roles in the physiology of eukaryotic organisms. For example cholesterol forms part of the cellular membrane where it modulates the cell membrane's fluidity and function and serves as secondary messenger in developmental signaling.

Plant sterols are also known to block cholesterol absorption sites in the human intestine thus helping to reduce cholesterol in humans.

[edit] See Also

• Cholesterol
• Phytosterol
• Ergosterol

[edit] External links

• Cholesterol Food Sources
• Plant Sterols -IFIC.org