Which of the following represents how easily the molecules cross a synthetic membrane composed of phospholipids but not proteins, from most easily (freely permeable) to least easily (not permeable)?
A)hydrophobic molecules, ions, small polar molecules, large polar molecules
B)hydrophobic molecules, small polar molecules, large polar molecules, ions
C)ions, large polar molecules, small polar molecules, hydrophobic molecules
D)small polar molecules, large polar molecules, ions, hydrophobic molecules
E)large polar molecules, small polar molecules, hydrophobic molecules, ions

Question

Quizplus · Accepted Answer

Phospholipid membranes are permeable to hydrophobic molecules and small polar molecules, but not to large polar molecules and ions. Therefore, the order from most permeable to least permeable would be hydrophobic molecules, small polar molecules, large polar molecules, ions, as listed in choice B.

Which of the Following Represents How Easily the Molecules Cross