Cell Membrane Fluid Motion

[FutureDoc2]

Okay for starters, sorry if this question has been asked me before, but I am really confused. Re-reading TBR Bio Section VI pg. 34, it states, " Phospholipids that have short-chain fatty acids and fatty acids with increasing sites of cis unsaturation tend to increase their mobility (i.e., fluidity) in the membrane. The greater the motion of the fatty acid side chains, the more fluid the membrane. Addition of cholesterol to a membrane acts to decrease fluidity.." and so forth. However, I always thought, cholesterol stabilized the membrane and gave the membrane fluidity. Am I wrong? Or did TBR make a typo? Thanks in advance...

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[Ineedhopenow]

Cholesterol makes the bilayer more rigid. I had the same confusion when I took cell biology.

Cholesterol stabilizes the membrane by making it less "flimsy".

 

[FutureDoc2]

Cholesterol makes the bilayer more rigid. I had the same confusion when I took cell biology.

Cholesterol stabilizes the membrane by making it less "flimsy".

Thank you so much! It was really throwing me off! haaa

 

[Lunasly]

I thought that temperature played a large role here? That is, at high temperatures, doesn't the cholesterol act to decrease fluidity because the phospholipids at this point are moving quickly, while at low temperatures cholesterol acts to increase fluidity since the phospholipids are moving slowly.

 

[FutureDoc2]

I thought that temperature played a large role here? That is, at high temperatures, doesn't the cholesterol act to decrease fluidity because the phospholipids at this point are moving quickly, while at low temperatures cholesterol acts to increase fluidity since the phospholipids are moving slowly.

Yes membrane fluidity is dependent on temperature. However, Cooler temperatures act to decrease membrane fluidity while higher temperatures act to increase it! If you have TBR Bio, check out pg 34 Section VI

 

[Lunasly]

Yes membrane fluidity is dependent on temperature. However, Cooler temperatures act to decrease membrane fluidity while higher temperatures act to increase it! If you have TBR Bio, check out pg 34 Section VI

Exactly, and doesn't cholesterol maintain the fluidity of the membrane in both cases? That is, at high temperatures, the cholesterol will decrease the fluidity while at lower temperatures it will increase temperature.