Question

According to the widely accepted theory "the 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 aspects. In this regard, which of the following statements is incorrect?

• A. Proteins in cell membranes can travel within the lipid bilayer
• B. Proteins can also undergo flip-flop movements in the lipid bilayer
• C. Proteins can remain confined within certain domains of the membranes
• D. Many proteins remain completely embedded within the lipid bilayer

Answer 1

The correct option is B Proteins can also undergo flip-flop movements in the lipid bilayer

The statement, "proteins can also undergo flip-flop movements in the lipid layer" is incorrect because flip-flop or transmembrane movement is the migration of lipid molecules from one lipid layer to another lipid layer.

The other statements are correct. Proteins in cell membranes can travel within the lipid bilayer because of the fluidity of the membranes. The statements about proteins being confined in certain domains and them being embedded within the bilayer tell about the presence of internal, external, and transverse proteins.