Part C -How does phospholipid structure relate to the selective permeability of the plasma membrane? A critical feature of the plasma membrane is that it is selectively permeable. This allows the plasma membrane to regulate transport across cellular boundaries–a function essential to any cell’s existence. How does phospholipid structure prevent certain molecules from crossing the plasma membrane freely? Drag the labels to fill in the table. Use only white labels for white targets, pink labels for pink targets, and blue labels for blue targets.