Cell Wall

• It is a non-living rigid structure found outer to the plasma membrane of fungi and plants.
• Cell wall of Algae is made of cellulose, galactans, mannans and minerals like CaCO3. In other plants, it consists of cellulose, hemicellulose, pectins and proteins.
• Cell wall of a young plant cell (primary wall) is capable of growth. It gradually diminishes as the cell matures and the secondary wall is formed on the inner side (towards membrane) of the cell.
• The middle lamella is a layer mainly of calcium pectate which glues the different neighbouring cells together. The cell wall and middle lamellae may be traversed by plasmodesmata which connect the cytoplasm of neighbouring cells.

Functions:

• a. It gives shape to the cell.
• b. It protects the cell from mechanical damage & infection.
• c. It helps in cell-to-cell interaction.
• d. It acts as barrier to undesirable macromolecules.