Question

Select the correct statement from the following regarding plasma membrane

• A. Lipids are arranged in a bilayer with polar heads towards the inner part.
• B. Fluid mosaic model of cell membrane was proposed by Singer and Nicolson.
• C. Na+ and K+ ions move across cell membrane by passive transport.
• D. Proteins make up 60 to 70% of the cell membrane

Answer 1

The correct option is B Fluid mosaic model of cell membrane was proposed by Singer and Nicolson.

The fluid mosaic model explains various observations regarding the structure of functional cell membranes. The model, which was devised by SJ Singer and GL Nicolson in 1972, describes the cell membrane as a two-dimensional liquid in which phospholipid and protein molecules diffuse easily. Statement (a) is false, as the lipids are arranged in a bilayer with polar heads pointing outwards. Statement (c) is false, sodium and potassium ions are actively transported across the cell membrane (via the Sodium-Potassium pump) Statement (d) is false, as most of the plasma membrane is composed of the lipid bilayer, with proteins embedded in between.