?

AP® Biology

Free Version

Upgrade subject to access all content

Easy

Cell Membrane Function

APBIO-E4LEFJ

A cell membrane controls what goes in and out of the cell. Because of the hydrophilic and hydrophobic regions of the phospholipid bilayer, small nonpolar molecules cross the membrane easily, while large and hydrophilic molecules cannot cross easily.

"Cell Membrane." Wikipedia. Wikimedia Foundation, n.d. Web. 10 Aug. 2016.

The term used to describe this differential movement of molecules across a membrane is

A

passive transport.

B

selective permeability.

C

osmosis.

D

diffusion.