Q. What is Cholesterol?

In its free, unesterified form cholesterol is a major component (together with phospolipid) of cell membranes. Its presence helps to stabilize membrane fluidity and therefore, the barrier between cell and environment. Cholesterol is also important as a precursor of steroid hormones and of bile acids. Cholesterol present in the plasma and extracellular fluid is largely in the esterified form.