Concept: The inner and outer leaflets of the plasma membrane have distinct compositions based on their differing cellular roles.

Solution: The membrane is asymmetrical because the two surfaces and halves are not identical. The outer leaflet contains glycoproteins and glycolipids (forming the glycocalyx) which are absent on the inner cytosolic leaflet. Furthermore, the specific types of phospholipids differ between the two halves.

Distractor Autopsy: Protein mobility (fluidity) and lipid bilayer orientation (hydrophobic inside) describe its fluid and barrier properties, not its asymmetry.