Cholesterol increases membrane fluidity

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In summary, cholesterol is a substance found in the body that can increase the risk of heart disease if there is too much of it in the blood. It can be controlled by maintaining a healthy lifestyle and diet, and in some cases, medication may be necessary. Cholesterol also plays a role in membrane fluidity, increasing it at low temperatures and decreasing it at high temperatures due to its unique structure.
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aychamo
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Hello there;

In class we learn that "cholesterol increases membrane fluidity at low temperatures, and decreases membrane fluidity at high temperatures." I can see how it would increase fluidity at low temperatures since it attachs to the lipid tails of the membrane, which would push them further apart, making them more fluid. But I can't see how it would decrease fluidity at high temperatures. The only thing I could rationalize is that cholesterol must absorb heat which would make the membrane components less energetic (less moving = less fluidity).

Does that sound about right?

Thank you
 
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  • #2
It was discussed before here https://www.physicsforums.com/showthread.php?t=65214

monique said:
Cholesterol has a very small head group and a bulky tail group with a rigid steroid ring structure, which cause it to be bend. This bending immobilizes surrounding phospholipids, thus making the membrane less fluid.
and
monique said:
That is because for a phase transition to occur from a liquid state to a rigid crystalline (gel) state, the hydrocarbon tails need to be closely packed and ordered.

1) cholesterol prevents interaction between hydrocarbon tails of lipids
2) cholesterol is bend and thus prevents close packing

So the membrane remains fluid at lower temperatures, than would normally be allowed.
 
  • #3
Ahh, understood. Thank you!
 
  • #4


Cholesterol is a waxy, fat-like substance that occurs naturally in all parts of the body. Your body needs some cholesterol to work properly. But if you have too much in your blood, it can stick to the walls of your arteries. This is called plaque. Plaque can narrow your arteries or even block them.

High levels of cholesterol in the blood can increase your risk of heart disease. Your cholesterol levels tend to rise as you get older. There are usually no signs or symptoms that you have high blood cholesterol, but it can be detected with a blood test. You are likely to have high cholesterol if members of your family have it, if you are overweight or if you eat a lot of fatty foods.

You can lower your cholesterol by exercising more and eating more fruits and vegetables. You also may need to take medicine to lower your cholesterol.
 
  • #5


hi! thanks a lot for your responses. I gained new insight about cholesterol. I was wondering if you can also post examples of your researches or investigatory projects regarding cholesterol? i badly need one for school and I don't know where to start.

http://www.all-about-lowering-cholesterol.com/diet-for-lowering-cholesterol.html" [Broken]
 
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1. What is cholesterol?

Cholesterol is a type of fat found in the cells of animals, including humans. It is an essential component of cell membranes and is involved in various biological processes.

2. How does cholesterol increase membrane fluidity?

Cholesterol is able to insert itself into the cell membrane, creating small spaces between the lipid molecules. This makes the membrane more flexible and fluid, allowing it to move and change shape more easily.

3. Why is membrane fluidity important?

Membrane fluidity is important for various cellular functions, including cell signaling, transport of molecules, and maintaining the shape and stability of cells. It also allows cells to respond to changes in their environment.

4. Can too much cholesterol in the membrane be harmful?

While cholesterol is important for maintaining membrane fluidity, having too much of it can be harmful. Excess cholesterol can cause the membrane to become too fluid, making it less stable and potentially affecting its functions.

5. How does cholesterol affect different types of cells?

The amount of cholesterol in the cell membrane can vary depending on the type of cell. For example, cells in the brain and nervous system tend to have higher levels of cholesterol in their membranes compared to other cells. This is because cholesterol is important for proper functioning of these cells.

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