Question

The special arrangement of lipids in the cell membrane ensures that the

• A. polar tail of saturated hydrocarbons is protected from the aqueous environment.
• B. non-polar tail of unsaturated hydrocarbons is protected from the aqueous environment.
• C. polar tail of unsaturated hydrocarbons is protected from the aqueous environment.
• D. non-polar tail of saturated hydrocarbons is protected from the aqueous environment.

Answer 1

Answer: (D)

The detailed structure of the membrane was studied only after the advent of the electron microscope in the 1950s. Meanwhile, chemical studies on the cell membrane, especially in human red blood cells (RBCs), enabled the scientists to deduce the possible structure of plasma membrane. These studies showed that the cell membrane is composed of lipids that are arranged in a bilayer. Also, the lipids are arranged within the membrane with the polar head towards the outer sides and the hydrophobic tails towards the inner part.This ensures that the nonpolar tail of saturated hydrocarbons is protected from the aqueous environment. The lipid component of the membrane mainly consists of phosphoglycerides.