Why does a phospholipid on the cytoplasmic side of the cell membrane rarely flip to the extracellular side if both environments are polar?
A)The polar head group cannot pass through the nonpolar interior.
B)The two sides have different functions and thus the phospholipid would not function properly.
C)The cytoplasmic phospholipid is too big to pass through the membrane.
D)The cholesterol does not allow lipids to move.

Question

Quizplus · Accepted Answer

The nonpolar interior of the membrane consists of hydrophobic fatty acid chains that repel the polar head group of the phospholipid, preventing it from flipping to the extracellular side. The polar head group cannot pass through the nonpolar interior. Additionally, the orientation of the phospholipids is critical for membrane function, and flipping from the cytoplasmic to the extracellular side can disrupt membrane integrity and function.

Why Does a Phospholipid on the Cytoplasmic Side of the Cell