What is Cell Wall? – Definition, Structure, Function

The life forms on our planet earth are many, and each of these life forms is comprised of millions of cells, that perform various important functions that play a vital role in the growth and evolution of the species. And these cells constitute multiple essential components including the cell wall, which play major roles in the above-mentioned processes.  

What is a Cell Wall?

For the students who are coming across this term for the first time, here’s a short description for you. The cell wall is defined as a non-living component that surrounds the inner layers and the components inside a cell. Besides, the cell wall acts as a protective layer for the components inside the cell, and not just that it also provides shape and support to the cell. Moreover, cell walls are commonly found in all types of eukaryotic organisms, like fungi and plants, however, in prokaryotic organisms, the cell walls are limited to only a few species. 

Structure of a Cell Wall

Before we delve into cell wall structure, firstly we have a look at the cell wall diagram.

Cell Wall Diagram

As explained in the cell wall diagram, the cell wall is the outermost layer of the cell, which is located right next to the plasma membrane. Moreover, the cell wall is comprised of generally three layers, which vary based on the type of organism. More importantly, these three layers are composed of carbohydrates like cellulose, pectin, hemicellulose, etc. These three layers are,  

• Primary Cell Wall – The thinnest layer inside the cell wall, which is located closer to the inside components of a cell, and mainly consists of structural proteins and pectic polysaccharides. The main function of these cell walls is to help the cells stretch as they grow in size and shape.  
• The Middle Lamella – Middle Lamella is the interface between two cells, that helps them be in contact with each other all the time. The middle lamella consists of components like proteins and lignin. 
• Secondary Cell Wall – The cell wall is formed inside the primary cell wall, and its major function is to provide waterproofing and rigidity to the cell. Moreover, this is the thickest layer of the cell wall, which generally provides the characteristic rectangular or square shape of the cell. 

Functions of a Cell Wall

The cell wall, a prominent feature in plant cells, serves multiple vital functions essential for the survival and functionality of the cell. Let’s delve into each of these cell wall function in more detail: 

• Protection from Mechanical Stress and External Forces: The cell wall acts as a sturdy outer barrier that protects from mechanical stress and external forces acting on the cell. It helps shield the delicate internal structures from damage caused by physical impacts or compression. 
• Strength, Rigidity, and Shape: One of the primary roles of the cell wall is to impart strength, rigidity, and characteristic shape to the cell. The cell wall’s structural integrity allows it to maintain its shape despite external pressures, contributing to the overall stability of the cell. 
• Regulation of Substance Transport: The cell wall facilitates the movement of essential substances such as water, nutrients, and proteins into and out of the cell. Pores and channels within the cell wall allow for selective permeability, regulating the passage of molecules and ions according to the cell’s needs. 
• Expansion and Contraction with Water Uptake: Water plays a crucial role in many cellular processes, and its uptake by the cell leads to the expansion of the cell wall. This expansion helps maintain turgor pressure, which is essential for cell growth and structural support. Conversely, when water is released, the cell wall contracts, aiding in the prevention of water loss from the cell. 
• Barrier Function: The cell wall serves as an effective barrier between the cell’s internal components and the external environment. It prevents the entry of harmful pathogens and toxins while allowing the passage of essential molecules necessary for cellular function. 

The cell wall of plant cells performs a diverse range of functions critical for the cell’s survival and functionality. From providing protection and structural support to regulating substance transport and maintaining turgor pressure, the cell wall is indispensable for the overall health and integrity of the cell. Its multifaceted nature underscores its importance in plant biology and cellular physiology. 

Conclusion

The above article helped you understand all about the functions of the cell wall, the structure of the cell wall, and the cell wall diagram. And if you want to learn more about the structure of plant cell, then please read the blog mentioned here. If you are looking for an Online Home Tutor program with multiple benefits, within your budget, then the Tutoroot platform might be a good choice for you.  

Frequently Asked Questions

Who discovered the cell wall?  

Robert Hooke discovered the cell wall in the year 1665.  

What is a cell wall made up of?  

Depending on the type of living organism, the cell wall is composed of a network of cellulose microfibrils, that is enclosed in cross-linking glycans, which in turn is embedded in a matrix of pectin polysaccharides that are cross-linked.  

What is cell wall Definition? 

A cell wall is a rigid, structural layer that surrounds the cell membrane of many organisms, providing support, protection, and shape to the cell. 

What is the nature of the cell wall in diatoms? 

In diatoms, the cell wall is made of silica, forming intricate and ornate structures called frustules. These silica-based cell walls provide strength and protection to diatom cells. 

Which cell does not have a perforated cell wall? 

Animal cells do not have a perforated cell wall. Instead, they have a flexible cell membrane that surrounds the cell, providing structure and protection. 

What is the function of the cell wall? 

The cell wall serves several functions, including providing structural support and rigidity to the cell, protecting the cell from mechanical stress and external forces, regulating substance transport in and out of the cell, and acting as a barrier between the cell’s internal components and the external environment.

Who discovered the cell wall? 

The cell wall was discovered and described by the early microscopist Robert Hooke in 1665. While examining thin slices of cork under a microscope, Hooke observed box-like structures and coined the term “cell” to describe them, referring to the small rooms or cells of a monastery. He recognized that these cells were surrounded by a rigid structure, which he termed the “cell wall.”