Plasma membrane is made up of which organic molecules?

The correct answer is option 3 i.e. Lipids and protein.

Plasma membrane, also called the cell membrane is mainly composed of lipids and proteins.

• The major lipids are arranged in a bilayer and called as phospholipids.
• Plasma membrane also contains cholesterol.
• Cell membranes also possess protein and carbohydrate as per Biochemical investigation.
• The ratio of lipid and protein varies in different cell types.
  • For example, in human beings, the membrane of the erythrocyte has approx 40 per cent lipids and 52 per cent protein.