Plant and animal cells have certain distinguishing features which sets them apart from each other. However, both plant and animal cells are built with certain structural layers and organelles that are responsible for various important functions within the cell. One such structural layer is cell wall. Cell walls are an integral part of a cell, and they play a pivotal role in maintaining the filtering mechanism of the cell.
But do plant cells have cell walls? Why do plant cells need cell walls in the first place? Find out why the cell wall is a crucial aspect of cells in this article.
What Are Cell Walls?
Before diving into the discussion, let’s have a look at what cell walls actually are.
All cells have an outer boundary. Cell wall is the outer boundary in some cell types. It is a rigid layer outside the cell which resides next to the plasma membrane. This rigid layer is due to the presence of a huge number of polysaccharides and the passive uptake of water.
Cell walls are known for their incredible support to the cell and its components. Besides, cell walls also have protective and filtering functions. They not only act as a boundary to the cells but have crucial roles in maintaining the growth of plants.
A cell wall is a distinct and specialized manifestation of the extracellular matrix in cells. It is mostly composed of cellulose, matrix polysaccharides, and proteins. Other than these compositions, cell walls serve as an important form of intercellular communications.
Do Plant Cells Have Cell Walls?
The cell wall is a distinct and integral part of plant cells. In fact, cell wall is a crucial differentiating point between plant and animal cells. Animal cells lack a cell wall, which is one of the main distinguishing features between plant and animal cell.
A cell wall forms the main framework for a cell. All the other structural layers and organelles are housed within the cell wall. The main reason why plant cells need cell wall is because of their continuous water transportation. Due to continuous water transportation, plant cells are always at risk of swelling and bursting out. A tough and rigid layer like cell wall protects the cell from expanding and keeps it at bay.
Cell walls have optimum control on the internal turgor pressure within the plant cells. They also have an important role in maintaining the osmolarity in plant cells. Besides, plant cell walls take part in hydration, transportation, protection, vitality, and survival.
The Role of Cell Walls in Plant Cells
Cell walls play a vital role in plant cells. Let’s have a look at how a cell wall functions in plant cells-
Providing Mechanical Support
The cell wall maintains the shape and size of the cell with the help of its rigid composition formed with cellulose and proteins. It provides mechanical strength to the entire cell and protects the cell from osmotic stress. Cell wall in plants also allows semi-permeability and provides the passage for cellular substances to move in and out of the cell easily.
Withstanding Internal Turgor Pressure
One of the most crucial roles of cell wall is withstanding the internal turgor pressure within the cells and preventing the cells from bursting with excess water transportation. The cell wall acts as a tough membrane for the plant cell and allows smooth water transport across the cell without expanding to a maximum extent.
Another important function of cell wall is to maintain intercellular communication by forming pores and channels called plasmodesmata. With the help of such kinds of intercellular communications, different signals can pass from one cell to another. The plant cells can form a strong support system among each other through this unique form of communication.
Protection Against Pathogens
The cell wall acts as an excellent barrier against pathogens like plant viruses, harmful bacteria, and so on. It prevents pathogens from entering the plant cell and disrupting the normal cellular function.
Cell wall acts as a storage for carbohydrates. These carbohydrates are later utilized by the plants for growth purposes. It is a common phenomenon among seeds of the plants.
What Are Cell Walls made Of
Cell walls are made of a combination of different substances. The majority of cell wall is occupied by cellulose molecules. However, cell walls also bear protein molecules and matrix polysaccharides.
Bacterial cell walls are composed of peptidoglycans, while fungal cell walls are formed with chitin. Algal cell walls also consist of polysaccharide molecules similar to plant cell walls. Most of the cell walls are composed of structural glycoproteins that perform a multitude of functions within the cell.
The cellulose molecules in a cell wall are arranged in a flat ribbon-like structure. Matrix polysaccharides within the cell wall are formed with hemicellulose and pectin. Pectin is a pectic polysaccharide that has a pivotal role in cell adhesion. On the other hand, hemicellulose includes xylans, glucans, and mannans. They form the structure of the walls and facilitate plant growth. The origin of both pectin and hemicellulose is from the Golgi apparatus of the plant cell.
Plant cell wall is also formed with many glycoproteins, mainly hydroxyproline and serine. Besides, other structural composition of the cell wall includes lignin, cutin, suberin, which have incredible role in providing stability and protection to the adjacent plant cells.
Can Plant Cells Survive Without Cell Walls
Man cannot survive without a house. Similarly a plant cell cannot survive without its cell wall. Plant cells need cell walls for their sustenance and survival.
If plant cells did not have cell walls, there would have been a high risk of the cells expanding due to excess internal pressure and bursting out. This would lead to the untimely death of the cell, and there would be no plant left in the world at some point.
Cell walls protect the plant cells from their cessation by maintaining their internal turgor pressure and ensuring stability within the cells. Besides, cell walls protect the cellular components from external impact and keep the organelles intact. If plant cells lacked cell walls, any external impact would’ve destroyed the cellular organelles, and plant life would have ceased to exist.
So, it can be said that, without cell walls, plant cells will never survive. This is why cell walls are termed as the savior of plant cells.
The Unique Abilities of Plant Cell Walls
One of the unique abilities of a plant cell wall is the ability to expand without undergoing any breakage. This is something applaudable as cells have many factors that can cause them to expand hugely. However, with the cell wall being a tough layer, this process is almost impossible. Cells can no longer expand with breakage and disruption in the presence of cell walls. As a result, it assists in the growth of the plant and prevents untimely death of the plant.
Bringing it to an end, it can be said that plant cells cannot function without a cell wall. From forming the framework to helping in different physiological functions of the cell, a cell wall is one of the most important parts of the cell.