Information AboutSterol |
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Sterols, or '''steroid alcohols''' are a subgroup of Steroid s 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 Plant s are called Phytosterol s and sterols of Animal s are called '''zoosterols'''. The most important zoosterols are Cholesterol and some Steroid Hormone s; 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. Plant sterols are also known to block cholesterol absorption sites in the human intestine thus helping to reduce cholesterol in humans. In humans sterols act to provide important signals and metabolic communications eg. circadian rhythms, blood clotting. SEE ALSO EXTERNAL LINKS REFERENCES Molecular Biology of the Cell (Alberts et al., 2002) {Link without Title} |
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