How Does Cholesterol Regulate Phospholipid Bilayer Fluidity?

💡 The Answer

• Cholesterol inserts between phospholipids, with its rigid steroid ring stiffening nearby tails.
• At high temperatures, cholesterol reduces fluidity by preventing excessive motion of tails.
• At low temperatures, it prevents tight packing of tails, acting as a fluidity buffer.
• This buffering enables membranes to function across a wide temperature range in mammals.