Cell wall and its role in the life of a plant cell

The cell wall is a rigid and dense membrane located above the cytoplasmic membrane. This element is typical for cells of bacteria, fungi and plants. In addition to protecting the cells, the rigid shell performs a number of other equally important functions.

Cell wall: general information

The cell wall of each organism has a number of characteristics. For example, in bacteria it consists mainly of murein. By the way, bacterial strains are divided into two types - gram-positive and gram-negative - precisely due to the structural features of the rigid shell. This determines their sensitivity to antibiotics.

If we talk about the cell walls of fungi, then their main components are chitin and glucans. But algae shells can consist of different polysaccharides - mainly glucose and its compounds. By the way, the composition of the cell membrane of algae is a very important taxon. It is worth remembering about the Diatom Algae group , whose representatives synthesize their own wall of silica.

Cellular wall of plants and its functions

The principles of the structure of a rigid cell membrane are most conveniently studied by the example of a plant cell. And although mechanical protection is one of the most important functions of the cell wall, it has a much greater significance:

• Provides mechanical and chemical resistance of the cell;
• Prevents cell rupture in a hypotonic environment;
• The cell wall is also an ion exchanger, since ion uptake and release through it take place;
• Takes part in the transport of organic compounds.

Structure of the cell wall

In the plant wall, it is common to distinguish three main components: a framework, a matrix and inlaying substances.

The cell wall of the plant consists of cellulose. Due to the formation of hydrogen bonds, the cellulose molecules form strong microfibrils that are immersed in the base material, or matrix.

The cell wall matrix is approximately 60% of its total mass. It fills the space between the microfibrils, and also creates strong bonds between the macromolecules, ensures the elasticity and strength of this cellular structure. The main components of the matrix are hemicellulose and pectin.

• Hemicellulose is a polysaccharide, similar in structure to cellulose, but with shorter and branched chains of monomers.
• Pectic substances also belong to polysaccharides, but they also contain residues of methyl alcohol. Thanks to the formation of chemical bonds with ions of calcium and magnesium, pectin takes part in the formation of the middle plates - the places where two adjacent cells are connected together. By the way, a lot of pectin is contained in the fruits of plants.

Encrusting substances are in most cases lignin, which is about 30% of the dry mass of the cell wall.

• Lignin can be deposited as a continuous layer, and in the form of separate elements - spirals, nets or rings. This substance acts as cement - it bonds the cellulose fibers together. Due to lignification, the cell wall becomes more resistant and less permeable. By the way, lignin is responsible for lignification of plants.

Quite often, such substances as kutin, suberin and wax are deposited on the outer surface of the cell membrane.

Suberin is deposited on the inner side of the cell membrane, providing a process of culling. Such a cell becomes absolutely impenetrable to moisture, so its content quickly dies off, and free space is filled with air.

The main function of wax substances and cuticles is to protect cells from infection, as well as to reduce the level of evaporation of water.

We can say that the cell wall is a very important element of the plant cell, which ensures its normal development.