The cell wall is the organelle that distinguishes the animal cell and plant cell, because those cell walls only locate at plant cell. Cell wall consist of cellulose embedded in a matrix of polysaccharides and proteins, it 10 – 100 times more thicker than plasma membrane that make this cell very rigid and strong, so cell wall can support the plant to stand up from the ground, protect from the fungi, and other harmful effect from its environment. Cell wall locates on the very outer of plant so the function that mention above can be fulfilled.
There are three primary sites that construct cell wall as a system of plant:
1. Primary cell wall is the major component of cell wall, it is flexible enough, so plant cell can continue growth (enlarge) and make the possibility of secondary growth of plant if the primary growth of plant has been reached. Primary cell wall locate at the very outer of cell wall its location same as epidermis on human skin. If we consider this cell as a tissue of plant, we can see through microscope that the cell and the other cell are adjacent to each other with primary cell walls that unite to other cell primary cell wall.
2. Secondary cell wall is some component that not every plant has in its cell wall. Sometimes plants generate secondary cell wall to strengthen the primary cell wall, it location if we consider same as human is under the epidermis (endodermis). This secondary cell wall deposited by plant inside of a layer that called plasma membrane.
Before the third site of cell wall, we must know there are 3 types (sometimes in many books 4 types) of cell junction in the cell of living things:
1. Tight junction, first and secondary membrane are pressed each other, and joined together by some protein.
2. Anchoring junction, it fastening cell like a strong sheet that produce by a sewing machine.
3. Gap junction is a connection that similar to a tunnel because it provides a way to molecules to transfer from one cell to another.
The multicellular organism cannot exist if it only consists of single cell so the cells need to communicate to each other. This principle same in the plant cell because plant cell has a rigid cell wall but they still need to communicate each other. The connection in the plant cell define as plasmodesmata (if consist of more than one plasmodesma). Through a plasmodesmata water and small molecules can transported to another cell, this system similar to the third connection (gap junction).
Reference :
Campbell et al.2008.Biology Concepts&Connection Sixth Edition.United States
