Cholesterol effect on membrane fluidity

Question 1

Cholesterol in a membrane

Answer 1

Cholesterol accounts for 20–25% of the mass of lipids in a typical membrane.

Question 2

Effect of fluidity at high temperatures

Answer 2

When the rigid (steroid) cholesterol molecules intercalate between the hydrocarbon chains of the membrane lipids, the mobility of fatty acyl chains in the membrane is restricted and fluidity decreases at high temperatures

Question 3

Effect of fluidity at low temperature

Answer 3

Cholesterol disrupts the ordered packing of the extended fatty acyl chains and thereby increases fluidity at low temperatures.