bis_104__pq_6_ans_ss_i_08 - Cholesterol tends to toughen...

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BIS PQ 6 SS I 08 6. Discuss the various factors that have an influence on the fluidity / viscosity of biomembranes. In your discussion, include the following factors: Lipid composition Lipid structure Cholesterol Temperature Lipid rafts Fluidity of a biomembrane is dependent on the types of lipids that make up that particular membrane; the relative proportions of the different lipid types determine the fluidity. Lipid structure itself plays a role since longer chain FAs and saturated FAs favor membrane viscosity, whereas short chain and unstuated FAs favor viscosity. The chain length and degree of saturation mainly affect the packing arrangement of the bilayer.
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Unformatted text preview: Cholesterol tends to toughen and make a membrane less fluid (also less permeable). Cholesterol also stabilizes a membrane against subtle temperature changes; it acts as a buffer to broaden the transition temperature so a membrane can remain functional over a broader temp range. Lipid rafts, because they are composed of relatively large integral membrane proteins, sphingomyelin and cholesterol, tend to create micro domains of low fluidity. Biomemranes tend to become more viscous as temperature is lowered, and more fluid at higher temps....
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This note was uploaded on 08/18/2008 for the course BIS 104 taught by Professor Scholey during the Summer '08 term at UC Davis.

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