It has to do with the type of bonds that exist in cellulose. So we saw that in glycogen, as well as starch, we have these bonds we call the alpha one four glycocitic bonds. And we said that these alpha one four glycocitic bonds create a helical structure, and the helical structure is perfect to store it as energy. On the other hand, in Cellulose, we have individual monosaccharides of glucose that are connected via beta one four glycocytic bonds. And as a result of these beta one four glycocitic bonds, cellulose doesn't have a helicopter structure. Instead, it has a linear structure.