Why does a cell need to maintain its shape? What happens if we take away the cytoskeleton from an animal cell or what happens if we take the cell wall from the plant cell?

The plant cell is much simpler to respond to. Plant cells, at least in the stem, depend on turgidity to stay straight. The cell wall is kept a solid rectangular prism by pressure from the central vacuole, which makes the stem straight. The opposite of turgidity is flaccidity, or wilting. The plant would wilt if the cell wall were absent. It should be noted that this only considers the effects on the cell's shape.

The effect in an animal cell would be less pronounced if, once again, we only take into account the effects that the change in shape would have. (The absence of a cytoskeleton or cell wall would be disastrous for cell division!) The main issue would be a decreased surface area-to-volume ratio. This is because a high surface area-to-volume ratio allows more substances to enter or exit the cell because it provides a greater surface area across which molecules may diffuse in relation to the volume of the cell. Cells that have a high surface area-to-volume ratio are usually flat and frequently dimpled or covered in villi. Without the cytoskeleton, the cell would naturally become spherical. To lose its shape would be to dramatically lower a cell's efficiency.

Removing the cytoskeleton from an animal cell can result in a loss of shape, impaired movement, and disrupted internal organization; removing the cell wall from a plant cell causes a loss of structural support, which can lead to cell collapse and possible damage. A cell's ability to maintain its shape is essential for its structural integrity, support, and proper functioning.