Structure and Support in Plants

The cell wall can be defined as a semi-rigid, thick structure that surrounds and protects the cell membrane of a few types of cells and also gives it a shape. In addition, the cell membrane alone cannot provide the structure and support needed.

Every living organism on this planet is composed of cells. These cells are responsible for multiple vital functions like metabolism, excretion, reproduction, etc. Intracellular structures combine and make cell-like organelles. Moreover, the organelles stick to the cytoplasm and perform some unique functions as well. The cell has a cell membrane around it that surrounds it and separates the contents of the cell from the external environment.

Cell Wall Functions

The primary job of a cell wall is to protect the internal structures of the cell. The plasma membrane or the cell membrane is said to be a weak layer that is not successfully able to provide the structure and support required by the contents of the cell in different conditions of the environment. Moreover, the cell walls are also responsible for providing shape to the cells. In case water enters inside the cell and increases the internal pressure of the cell, the cell wall prevents the cell from expanding.

The passage of molecules across the cells is also controlled by the cell wall, which allows only tiny metabolic molecules to pass. Therefore, it protects the cell from various drugs and toxins. When it comes to multicellular organisms with cell walls, they assist in the adhesion of cells and provide them with a shape.

Cell Wall Functions in Plants

In plants, the cell wall is responsible for plant turgidity. The cell wall provides structure and support to the cell. It helps to avoid the bursting of the cell when there is too much water in the cell. Moreover, the cell becomes able to survive in the osmotic pressure generated by the molecules of the water. Some plants have a cell wall that has only one layer, whereas other plant cells comprise two layers – primary and secondary. The secondary layer helps in making the cell water-resistant.

Components of the Cell Wall

The comprehensive chemical structure and physical arrangement of primary and secondary wall layers are different. However, their basic structure remains the same. 

The cell wall is made up of cellulose fibres with high stiffness integrated into the surface mixture of polysaccharides and systemic glycoproteins. The series of cellulose microfibrils and inter glycans are composed of a pectin polysaccharides matrix that is strongly linked. Secondary cell walls also contain lignin.

The Cell Wall of Bacteria

All types of bacteria do not have a cell wall. However, it is also worth noting that 90% of bacteria have cell walls. Most bacterial organisms have a cell wall outside the cell membrane. It is an added layer with a semi-rigid framework that normally provides strength, which the cell membranes appear to lack.

Bacteria generally have one of the following two types of cell walls:

• A gram-positive cell wall 

• A gram-negative cell wall 

The bacterial cell wall is made up of peptidoglycan. Peptidoglycan, also known as murein, is a component found in both gram-positive and gram-negative cell walls. The former has a thicker layer of murein than the latter. Aside from being present in the cell walls of bacteria, this substance has not been discovered anywhere on earth. 

Both types of bacterial cell walls contain added ingredients. This aspect makes the bacterial cell wall a complicated framework in a broad sense, especially compared to the cell walls of eukaryotic microbes. 

Cell walls of eukaryotic microbes have a single active component, such as cellulose in algal cell walls and chitin in fungal cell walls. The cell wall in fungi is located externally on the plasma membrane.

Presence of Cell Wall

The relatively rigid layer, the cell wall, surrounds the cell from outside the plasma/cell membrane. It offers extra security and protection. The cell wall is present in single-celled organisms. Thus, it is present in bacteria, archaebacteria, microbes, fungi, germs, yeasts, microorganisms, plants and algae. Animals and the majority of other protozoans have cell membranes. These structures, however, are not enveloped by cell walls. 

Conclusion

The cells of plants have features that include chloroplasts, intracellular vacuoles, as well as cell walls. The process of photosynthesis occurs in chloroplasts; the cell walls permit the plants to have strength in their structures. Moreover, the vacuoles help to control the handling of water by cells and the storage of various other molecules.