Question

According to 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 are incorrect -

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

Answer 1

The correct option is A Proteins can also undergo flip-flop

movements in the lipid bilayer

An improved model of the structure of cell membrane was proposed by Singer and Nicolson (1972) widely accepted as fluid mosaic model. According to this, the quasi-fluid nature of lipid enables lateral movement (Flip-flop) of proteins within the overall bilayer. This ability to move within the membrane is measured as its fluidity.

So, the correct answer is 'Option A'.