How does cholesterol affect lipid bilayer?

Hint: Cholesterol is a material that is waxy, fat-like and found in all the cells in the human body. It generates hormones, vitamin D, and substances that help to digest the food. All animal cells biosynthesize cholesterol and it is an important structural part of the membranes of animal cells.

Complete answer:
Cholesterol is a sterol or an organic molecule. Cholesterol is a type of lipid. Chemically, a lipid is classified as a water-insoluble substance that is soluble in alcohol, ether, and chloroform. A significant component of living cells is lipids. Lipids are the primary components of plant and animal cells, along with carbohydrates and proteins. Lipids are cholesterol and triglycerides. When cholesterol is present in large quantities, it works by adding conformational ordering of the lipid chains as a permeability barrier for the membrane. Although maintaining the membrane fluid, it improves its mechanical stiffness. This is in contrast to the case of low cholesterol levels, where bilayer permeability has increased significantly across the phase temperature spectrum. Cholesterol does not favor one lipid process to another when present in tiny quantities. At low cholesterol concentrations, it results in a very narrow coexistence area. Cholesterol makes the lipid bilayer less deformable by decreasing the mobility of the first few carbon groups of the phospholipid molecules' hydrocarbon chains and thereby decreases the permeability of the bilayer to small water-soluble molecules.
Cholesterol has distinct effects on membrane fluidity, depending on the temperature. Cholesterol interferes with the phospholipid fatty acid chains' movement at high temperatures. It reduces fluid in the outer part of the membrane and reduces its permeability to tiny molecules.
Therefore, cholesterol does affect lipid bilayer.

Note:
An increased risk of cardiovascular disease is associated with high cholesterol. Coronary heart disease, stroke, and peripheral artery disease may be part of it. Diabetes and high blood pressure have also been linked to high cholesterol.