the cell wall gives a plant cell a definite size and shape. because a plant dose not have any bones to give it support the plant needs to have support in other ways. this support comes from the cell wall. each cell is pressed and connected to the other cells that surround it. each cell has its own cell wall. all of these individual cell walls build a strong support system for the plant, allowing it to stand upright. this allws plants to capture the sun's energy