Which functions of a cell membrane would be compromised if the membrane consisted of a phospholipid bilayer without proteins? What about a membrane without phospholipids? Solution Without the membrane proteins, cell to cell interaction and transport of molecules across the membrane are not possible. The membrane receptor proteins help cell communication with the use of hormones, neurotransmitters, and other signalling molecules. Transport proteins through facilitated diffusion transport of molecules across the membrane. Structural proteins help to give the cell support and shape..