What is true about plasma membranes in all cells?
1 They occur in an uninterrupted bilayer with membrane proteins only in the internal surface.
2. They are two-sided; i.e., the cytoplasmic side is different from the external side.
3. They can allow all ions to move through the membrane.
4. They have hydrophilic tails in the interior of the membrane.
5. They dissolve in the surrounding solution.