Final answer:
Cholesterol impacts the fluidity of phospholipids within a cell membrane by acting as a buffer to temperature changes, increasing cell membrane fluidity at lower temperatures and decreasing fluidity at higher temperatures to maintain its functionality.
Step-by-step explanation:
True, cholesterol can be affected by temperature, which in turn changes the fluidity of phospholipids. Cholesterol present in animal cell membranes tends to dampen temperature effects. At lower temperatures, it prevents the membrane from becoming too rigid, maintaining fluidity. In contrast, at higher temperatures, cholesterol makes the membrane less fluid, controlling its permeability. The cholesterol essentially acts as a buffer to extend the range of temperature within which the membrane maintains its necessary fluidity to function properly. Additionally, cholesterol is involved in organizing clusters of transmembrane proteins into lipid rafts, serving more than just a role in membrane fluidity.