http://www.cholesterolrevealed.com/cholesterol-answers/what-is-the-importance-of-cholesterol-in-the-plasma-membrane Cholesterol Questions & Answers Fri, 02 Dec 2011 10:20:58 +0000 http://wordpress.org/?v=2.8.4 hourly 1 http://www.cholesterolrevealed.com/cholesterol-answers/what-is-the-importance-of-cholesterol-in-the-plasma-membrane/comment-page-1#comment-619 Inground Pool Supplies Thu, 30 Apr 2009 21:15:13 +0000 http://www.cholesterolrevealed.com/cholesterol-answers/what-is-the-importance-of-cholesterol-in-the-plasma-membrane#comment-619 In the lab, you can perform a Temperature of Melting Experiment, where you freeze the membranes (in actual biological cells, the cells cannot freeze) and measure the temperature at which the phase transition from the solid to liquid state takes place. Cholesterol can have dual functions in the cell -- it is both a regulator of membrane fluidity and it acts as an anti-freeze. Cholesterol makes the cell membranes more "sticky". This makes the membrane more viscous (less fluid). However, because cholesterol can also act as an "anti-freeze," this means that it is harder to promote the solid to liquid phase transition (the Tm experiments requires that the cell be frozen first). Therefore, the Tm is lower. This is somewhat misleading because this is the reverse of the typical effect of viscosity on Tm (a more viscous membrane has a higher Tm). In the lab, you can perform a Temperature of Melting Experiment, where you freeze the membranes (in actual biological cells, the cells cannot freeze) and measure the temperature at which the phase transition from the solid to liquid state takes place.
Cholesterol can have dual functions in the cell — it is both a regulator of membrane fluidity and it acts as an anti-freeze. Cholesterol makes the cell membranes more “sticky”. This makes the membrane more viscous (less fluid).
However, because cholesterol can also act as an “anti-freeze,” this means that it is harder to promote the solid to liquid phase transition (the Tm experiments requires that the cell be frozen first). Therefore, the Tm is lower. This is somewhat misleading because this is the reverse of the typical effect of viscosity on Tm (a more viscous membrane has a higher Tm).

]]> http://www.cholesterolrevealed.com/cholesterol-answers/what-is-the-importance-of-cholesterol-in-the-plasma-membrane/comment-page-1#comment-620 ~Amelie~ Thu, 30 Apr 2009 21:15:13 +0000 http://www.cholesterolrevealed.com/cholesterol-answers/what-is-the-importance-of-cholesterol-in-the-plasma-membrane#comment-620 cholesterol hinders the tight packing together of fatty acid molecules in the plasma membrane and increases membrane fluidity. cholesterol hinders the tight packing together of fatty acid molecules in the plasma membrane and increases membrane fluidity.

]]>