The relative impermeability of membranes to water soluble molecules is a result of
A) the nonpolar nature of water.
B) the presence of large proteins that extend through both sides of membranes.
C) the presence of inorganic salt crystals scattered through some membranes.
D) the presence of cellulose and waxes.
E) the presence of phospholipids in the lipid bilayer.

Question

Quizplus · Accepted Answer

The presence of phospholipids in the lipid bilayer is what makes membranes relatively impermeable to water soluble molecules. Phospholipids have hydrophobic tails that face inward and hydrophilic heads that face outward, creating a barrier that is difficult for water soluble molecules to penetrate.

The Relative Impermeability of Membranes to Water Soluble Molecules Is