Question

The plasma membrane is the boundary between a cell's internal and external environments. Both environments are aqueous.

To allow the separation of these aqueous environments, the regions of the plasma membrane indicated in the diagram have which of the following properties?

• A. (X) hydrophilic layers on the outside and (Y) hydrophobic layers on the inside of the membrane.
• B. X and Y are both hydrophobic layers.
• C. (X) hydrophobic layers on the outside and (Y) hydrophilic layers on the inside of the membrane.
• D. X and Y are both hydrophilic layers.

Answer 1

Answer: (A)

Fatty acid heads are hydrophilic in nature, and their hydrocarbon tails are hydrophobic in nature. Lipids found in plasma membrane form bilayer in such a way that their hydrophilic head faces outside and hydrophobic hydrocarbon tail is sandwich between hydrophilic heads.