Which of the following is NOT a plasma protein?

Cholesterol is not classified as a plasma protein; it is a type of lipid. Plasma proteins are primarily involved in various functions within the bloodstream, including maintaining osmotic pressure, facilitating immune responses, and aiding in blood clotting.

Albumins serve to regulate osmotic pressure and transport substances in the blood. Globulins play crucial roles in immune function and transport, while fibrinogen is essential for clot formation during the hemostatic process. Since cholesterol functions primarily as a structural component of cell membranes and as a precursor for steroids and bile acids, it does not fit into the category of plasma proteins. This distinction highlights the specific biological roles that plasma proteins occupy in maintaining health and homeostasis in the body.