Which structure forms a strong, supporting layer around the membrane and is found outside the cell membrane in plants and other organisms?

Which structure forms a strong, supporting layer around the membrane and is found outside the cell membrane in plants and other organisms?

• A. Cell wall
• B. Cytoskeleton
• C. Lipid bilayer
• D. Golgi apparatus

Answer: (A)

The key idea is a cell wall, which is a rigid layer that sits outside the plasma membrane and provides structural support. In plants and many other organisms, this outer shell helps maintain shape and resists the tug of osmotic pressure that could swell and burst a cell in hypotonic solutions. The cell wall is made of different materials depending on the organism: cellulose in plants, chitin in fungi, and peptidoglycan in bacteria. This external, sturdy layer distinguishes it from the membrane itself. The other options don’t fit this description. The cytoskeleton is an internal network inside the cell that helps with shape and movement, not an external shell. The lipid bilayer is the membrane itself, not outside of it. The Golgi apparatus is an internal organelle involved in modifying and shipping molecules, not a protective outer layer.

The key idea is a cell wall, which is a rigid layer that sits outside the plasma membrane and provides structural support. In plants and many other organisms, this outer shell helps maintain shape and resists the tug of osmotic pressure that could swell and burst a cell in hypotonic solutions. The cell wall is made of different materials depending on the organism: cellulose in plants, chitin in fungi, and peptidoglycan in bacteria. This external, sturdy layer distinguishes it from the membrane itself.

The other options don’t fit this description. The cytoskeleton is an internal network inside the cell that helps with shape and movement, not an external shell. The lipid bilayer is the membrane itself, not outside of it. The Golgi apparatus is an internal organelle involved in modifying and shipping molecules, not a protective outer layer.