According to the widely accepted "fluid mosaic model", cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect:
1. | Proteins can also undergo flip-flop movements in the lipid bilayer |
2. | Many proteins remain completely embedded within the lipid bilayer |
3. | Proteins in cell membranes can travel within the lipid bilayer |
4. | Proteins can remain confined within certain domains of the membrane |