Structure of Cell Wall

The cell wall’s primary functions are to provide structure, support, and protection to the cell. In many plants, the cell wall is composed primarily of cellulose and has three layers. The three layers are the middle lamella, primary cell wall, and secondary cell walls.

Structure of cell wall

The cell wall of plant cells covers the plasma membrane and offers tensile strength and resistance to mechanical and osmotic stress. It also enables cells to create turgor pressure, or the pressure of cell contents against the cell wall.

Plant cell walls are multi-layered and can have up to three sections. These layers are identified as the middle lamella, primary cell wall, and secondary cell wall, beginning with the outermost layer of the cell wall. While every plant cell has a middle lamella and a primary cell wall, not every cell has a secondary cell wall.

Layers of the cell wall

The three layers of the cell wall are:

Middle lamella: This outer cell wall layer comprises polysaccharides known as pectins. Pectins aid in cell adhesion by allowing adjacent cell walls to bind to one another. 

Primary cell wall: This layer develops between the middle lamella and the plasma membrane in developing plant cells. It is mostly made up of cellulose microfibrils that are held together by a gel-like matrix of hemicellulose fibres and pectin polysaccharides. The primary cell wall gives the cell the strength and flexibility it requires to grow.

Secondary cell wall: This layer forms between the primary cell wall and the plasma membrane in some plant cells. The primary cell wall may thicken to form a secondary cell wall after it has stopped dividing and growing. This rigid layer protects and strengthens the cell. Some secondary cell walls contain lignin in addition to cellulose and hemicellulose. In-plant vascular tissue cells, lignin strengthens the cell wall and improves water conductivity.

The function of cell wall

• The cell wall provides mechanical strength and support. It also regulates the direction in which cells grow.

• Plasmodium plasmodesmata allow cells to communicate with each other.

• Turgor pressure occurs when the cell’s contents push the plasma membrane against the cell wall. This pressure aids in the rigidity and erectness of a plant, but it can also cause a cell to rupture.

• Carbohydrates are stored in the cell wall of plants, particularly seeds, for use in their growth.

• In order to divide and grow, the cell wall sends signals to the cell to enter the cell cycle.

• The cell wall also controls diffusion. The porous cell wall allows some substances to pass through while keeping others out.

• Plant viruses and other pathogens are kept out by the cell wall, which acts as barriers.

Structure of yeast cell wall 

Yeast cells differ from cells in plants, animals, and bacteria in terms of structure and function.Yeast is a single-celled fungus that is widely used in the food, beverage, and pharmaceutical industries. When yeast cells go without food, their cytoplasm becomes more acidic, and proteins interact, making the cytoplasm less fluid. In the absence of an energy source, cell activity slows down to keep the cell alive.

The cell’s shape is determined by the cell wall, which also protects the cell from external threats. Polysaccharides in the cell wall, such as chitin, provide strength and support. Chitin is a protein that helps cells divide normally. Mannoproteins and β-glucans are also found in the cell walls of yeast. These elements are covalently linked to form macromolecular complexes, which are then assembled to form a complete wall. A yeast cell wall has many parts.

Parts of yeast cell 

• Cytoplasm

• Nucleus

• Cell membrane

• Mitochondrion

• Chitin cell wall

• Vacuole

Conclusion

Many cells, including plants, fungi, algae, bacteria, and yeast, have a cell wall as an outer protective membrane. Animal cells lack a cell wall. Yeast cells differ from cells in plants, animals, and microbes in their structure and function. Yeast is a multicellular, single-celled fungus that is important in the food, beverage, and pharmaceutical industries. Every organism has a different cell wall structure. Many animals don’t have a cell wall and thus grow in any shape.