Question

Which of the following statements about the plasma membrane is TRUE?

• A. It allows selected molecules to pass into and out of the cell.
• B. It is a rigid and unmoving layer of phospholipids and protein.
• C. It is a solid layer of protein that protects the contents of the cell.
• D. The plasma membrane of a bacterium has none of the same components as the plasma membrane of an animal cell.

Answer 1

Answer: (A)

Plasma membrane or the cell membrane which is made up of phospholipid bilayer with embedded proteins. It is a semipermeable membrane which allows ions and selected molecules to pass in and out of the cell. In bacteria, the cell wall is attached to the plasma membrane and plays the same role as a semipermeable membrane. The plasma membrane protects the cell from the outside environment.