Cell Wall
- In fungi and plants, a non-living and rigid structure known as the cell wall forms an outer covering for the plasma membrane. The cell wall serves multiple crucial functions.
- Functions of Cell Wall:
- The cell wall not only provides structural support and shape to the cell but also offers protection from mechanical damage and infections.
- Additionally, it plays a role in cell-to-cell interactions and acts as a barrier to unwanted macromolecules.
- Composition in Algae:
- Algae possess cell walls composed of cellulose, galactans, mannans, and minerals such as calcium carbonate.
- These components vary depending on the type of algae.
- Composition in Plants:
- In other plants, the cell wall is made up of cellulose, hemicellulose, pectins, and proteins.
-The composition may change as the cell matures.
- Primary and Secondary Wall:
- In young plant cells, the primary wall is capable of growth. However, as the cell matures, the secondary wall forms on the inner side, towards the membrane.
- The primary wall growth diminishes over time.
- Middle Lamella:
- The middle lamella is a layer primarily composed of calcium pectate.
- It functions to hold or glue adjacent cells together, contributing to the structural integrity of the plant.
- Plasmodesmata:
- Cell walls and middle lamellae may contain plasmodesmata, channels that connect the cytoplasm of neighboring cells.
- These channels facilitate communication and the exchange of materials between adjacent plant cells.