ANATOMY

Detailed explanation-1: -Cholesterol contains a tetracyclic ring structure and adopts a trans conformation, rendering the molecule a planar and rigid characteristics that increases membrane packing and contributes to the integrity and rigidity of cell membranes.

Detailed explanation-2: -Comprising 30 mol % of the lipids in cell membranes, cholesterol plays vital biophysical roles in monolayer and bilayer membranes. It increases the lipid-packing density and maintains high membrane fluidity.

Detailed explanation-3: -One of cholesterol’s functions is to reduce the fluidity of the membrane.To do so, it forms strong interactions with phospholipids using its rigid steroid ring structure. At high temperatures, these interactions stiffen the membrane and interfere with phospholipid mobility.

Detailed explanation-4: -The length of the fatty acid tail impacts the fluidity of the membrane. This is because the intermolecular interactions between the phospholipid tails add rigidity to the membrane.