Basic structure of cell wall

The cell is the basic structural unit if all plant tissues. These cells are surrounded by cell walls that provide an elastic support for retaining the contents of the cell.

Strength and elasticity are gained by use of several cross-linked polymers of different elastic properties, with an adhesive cementing structures together.

The cell also has a membrane layer, which is located just inside the cell wall and which controls the passage of liquids into and out of the cell. The cell is filled with jelly-like substance, termed the cytoplasm, which is composed of protein, sugars, salts and other substance dispersed in water.

Mature cells also contain vacuoles, which are separate compartments filled with a fluid, cell-sap and which are composed of dissolved sugars, salts, organic acids, pigments and other materials.

Also located within the cytoplasm are separate inclusion bodies, called plastids, which contains the pigment of chlorophyll. These plastids are only both 4 to 10 nm in diameter. The plant cell wall plays important roles in controlling cell differentiation.

The thin cell wall of a young cell, called the primary cell wall, contains many enzymes including not only glycosyl hydrolases, which simply disassemble cell wall polysaccharide, but also cell wall modifying enzymes such as expansin, endoxygloglucan transferase and pectinmethyl esterase.
Basic structure of cell wall