In what ways are proteins used by the cell membrane?

Answer 1

1. Channel proteins and carrier proteins are used for facilitated transport and active transport of materials that can't simply diffuse between the phospholipids.
2. Proteins on the outer surface act as identification "badges" for the organism to be able to recognize its own cells.
3. Proteins on the inner surface act as anchorage sites for the cytoskeleton.

Answer 2

For communication, for one. First thing that came to my mind. . .