Which item would NOT be listed as an example of boundary membranes?

Which item would NOT be listed as an example of boundary membranes?

• A. Mitochondria
• B. Skin
• C. Plasma membranes of cells
• D. Organelle membranes

Answer: (A)

Boundary membranes define borders between compartments at the organismal or cellular level. The skin forms the outer boundary of the body, the plasma membranes enclose the contents of each cell, and organelle membranes create internal boundaries around the organelles themselves. Mitochondria do have membranes, but they are internal boundaries that enclose the mitochondrial matrix within the cell, not boundaries that define the overall exterior or a major cellular compartment. So, in this sense, mitochondria aren’t listed as boundary membranes.

Boundary membranes define borders between compartments at the organismal or cellular level. The skin forms the outer boundary of the body, the plasma membranes enclose the contents of each cell, and organelle membranes create internal boundaries around the organelles themselves. Mitochondria do have membranes, but they are internal boundaries that enclose the mitochondrial matrix within the cell, not boundaries that define the overall exterior or a major cellular compartment. So, in this sense, mitochondria aren’t listed as boundary membranes.