Which element is found in the composition of the primary cell wall?

The primary cell wall of plants is primarily composed of cellulose, which is a polysaccharide made up of long chains of glucose molecules. This structure provides the necessary strength and rigidity to the plant cell, allowing it to maintain its shape and resist external pressures. Cellulose forms the framework of the cell wall, while other components, such as hemicellulose and pectin, also play supportive roles, but cellulose is the critical structural element.

In contrast, lignin is not typically found in primary cell walls; it is more prevalent in secondary cell walls, where it provides additional strength and waterproofing. Chlorophyll is a pigment essential for photosynthesis but does not contribute to the cell wall structure itself. Starch is a storage carbohydrate in plants and does not form part of the cellular structural components like the primary cell wall. Hence, cellulose is the defining component that makes the primary cell wall strong and supportive for plant cells.