The plant cell wall is made up of long, sturdy microfibrils of cellulose.
A microfibril assembles between sixty and seventy cellulose molecules, each in turn consisting of five hundred cellulose molecules. glucose chained linearly. The cellulose microfibrils are held together by a matrix formed by glycoproteins (sugar-linked proteins) and two polysaccharides, hemicellulose and pectin.
This molecular structure resembles reinforced concrete, where long and resistant iron rods, corresponding to cellulosic microfibrils, are dipped in a cement and stone mortar, corresponding to the matrix of glycoproteins, hemicellulose and pectin.
The cellulosic wall secreted shortly after cell division is the primary wall. This wall is elastic and accompanies cell growth. After the cell has reached its final size and shape, it secretes a new wall internally to the primary wall. This is the secondary wall.
Plant cell specializations are always associated with the structure of cell walls. In different plant tissues cells have different walls of different thickness, organization and chemical composition, which determine not only the shape but also the function of cells.