The effect of cholesterol on membrane fluidity at physiological temperatures is to Choose one: A. prevent lateral movement of ph
ospholipids and thereby decrease membrane fluidity in that region. B. maintain membrane fluidity due to exclusion of saturated glycerophospholipids. C. rigidify membranes by forming a complex that bridges the inner and outer leaflets. D. maintain membrane fluidity through its disruption of fatty acid packing.
The correct answer is D. maintain membrane fluidity through its disruption of fatty acid packing.
Explanation:
<u>Cholesterol</u> is a steroid lipid and is a constituent of biological membranes. It regulates the <em>fluidity</em> of the membrane (so, option C is not correct). Since cell membranes are composed of another type of lipids, the phospholipids, which form a bilayer, cholesterol distributes between the phospholipid tails and avoids these molecules pack each other forming rigid clusters. Thus, the option which better explains the effect is <em>D. maintain membrane fluidity through its disruption of fatty acid packing.</em>
