Final answer:
Cell walls help maintain a cell's shape by providing structural support and serving as a site for biochemical reactions. They are crucial for maintaining the integrity of cells, especially in plants, fungi, and certain bacteria.
Step-by-step explanation:
They perform this role by pushing against the plasma membrane, which helps the cell maintain its structural integrity. Additionally, the cell wall provides a site for many of the biochemical reactions of the cell. It's important not to confuse the cell wall with the cytoskeleton, which is a network of protein fibers found within the cell that also helps to maintain the cell's shape, secures organelles in specific positions, permits cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently.