The part of the plasma membrane that is in contact with the external environment of the cell consists of ________ molecules.
A) hydrophobic portions of the constituent
B) hydrophilic portions of the constituent
C) neutral (uncharged)
D) nonpolar ends of the constituent

Question

Quizplus · Accepted Answer

The hydrophilic portions of the lipid and protein molecules in the plasma membrane are in contact with the external environment of the cell, as they are attracted to water and other polar molecules. The hydrophobic portions of these molecules face inward, away from the aqueous environment, and form the interior of the membrane. Neutral and nonpolar molecules may also be present, but they do not make up the part of the membrane in contact with the external environment.

The Part of the Plasma Membrane That Is in Contact