NEET BIOLOGY

Detailed explanation-1: -The cholesterol molecules enhance the permeability-barrier properties of the lipid bilayer. They orient themselves in the bilayer with their hydroxyl groups close to the polar head groups of the phospholipid molecules.

Detailed explanation-2: -Abstract. The role of cholesterol in bilayer and monolayer lipid membranes has been of great interest. On the biophysical front, cholesterol significantly increases the order of the lipid packing, lowers the membrane permeability, and maintains membrane fluidity by forming liquid-ordered–phase lipid rafts.

Detailed explanation-3: -The cholesterol holds the phospholipids together so that they don’t separate too far, letting unwanted substances in, or compact too tightly, restricting movement across the membrane.

Detailed explanation-4: -Cholesterol molecules insert into the bilayer with their polar hydroxyl groups close to the hydrophilic head groups of the phospholipids (Figure 2.47). The rigid hydrocarbon rings of cholesterol therefore interact with the regions of the fatty acid chains that are adjacent to the phospholipid head groups.

Detailed explanation-5: -Hydrogen bonding and electrostatic attractions (ionic bonds) occur between the hydrophilic groups of phospholipids and the aqueous solution. We say that hydrophobic forces cause the bilayer to form, and the other weak forces stabilize the bilayer.