Question

Cell membrane is mainly constituted by lipids, proteins and carbohydrates. With respect to their mutual proportions, which of the following statement is correct?

• A. All the three are in equal proportions.
• B. Lipids are in least proportion.
• C. Proteins are in least proportion.
• D. Carbohydrates are in least proportion.

Answer 1

Answer: (D)

Carbohydrates are in least proportion.

Plasma membrane is the outer covering of cell made up of the phospholipid bilayer. Chemically, cell membrane or plasma membrane is composed of proteins (20 - 70 %), lipids (20 - 79 %), carbohydrates (1 - 5 %) and water (20 %). Nucleic acids, i.e., DNA and RNA are absent. Thus, the correct answer is option D.