Question

Why is there an incorporation of more cholesterol into the membrane?

1) This is likely because cholesterol will decrease membrane fluidity.
2) This is unlikely because bacteria do not contain cholesterol under any conditions.
3) This is unlikely because cholesterol will dissolve membrane phospholipids.
4) This is likely because cholesterol will increase membrane fluidity.

Answer 1

Cholesterol is incorporated into cell membranes to modulate fluidity, acting as a buffer against temperature changes and maintaining membrane integrity by filling spaces between fatty acids to decrease excessive fluidity. The correct option is 1) This is likely because cholesterol will decrease membrane fluidity.

Step-by-step explanation:

There is an incorporation of more cholesterol into the membrane because cholesterol has a specific role in modulating the fluidity of the membrane. Cholesterol serves as a buffer against changes in temperature, by preventing the membrane from becoming too fluid at high temperatures and too rigid at lower temperatures. This function is vital for maintaining the membrane's integrity and function across various temperatures. Animal cell membranes are rich in cholesterol, which, contrary to increasing fluidity, actually decreases it at higher levels by filling spaces between fatty acids in the hydrophobic interior of the membrane, thus restricting the movement of phospholipids and other membrane components.