Based on the fluid mosaic model of cell membranes, which of the following statements about membrane phospholipids is true? They frequently leave the bilayer and dissolve in the surrounding solution.
The hydrophilic regions of phospholipids are exposed to the cytosol and extracellular environment.
They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane.
They frequently flip-flop from one side of the membrane to the other.