True or False: All human cells have cell walls.

• A. True
• B. False
• C. Not applicable to human cells
• D. Depends on cell type

Answer: (D)

Cell walls are rigid protective layers found in many organisms, but human cells are enclosed only by a plasma membrane. The structural support for human cells comes from the cytoskeleton and, at the tissue level, the extracellular matrix, not from a cell wall. Therefore the statement is false: all human cells do not have cell walls. In pharmacology terms, how a compound crosses into a human cell depends on the properties of the plasma membrane and its transport mechanisms, not on a cell wall. There isn’t a human cell type that has a cell wall, so saying it depends on cell type isn’t correct for humans.