The cell membrane is a flexible structure that surrounds both plant and animal cells. The arrangement of molecules within the cell membrane makes it semi-permeable. That is, the cell membrane allows some substances to easily diffuse into and out of the cell, but it prevents the diffusion of other substances.
Plant and animal cell diagram
The cell wall is a rigid structure that surrounds plant cells. The materials found in the cell wall protect the plant cells and give plants structural support.
