Cell Wall is made up of What?

Introduction:

All plant cells, except the germ cells of some plants and higher classes of plants, have a cell wall outside the plasma membrane composed of cellulose derived from the protoplasm is called a cell wall. It is an outermost layer of a plant cell except for the animal which has a vital role in cooperating with every component in many other important functions.

Physical Structure: 

The cell wall of a mature plant cell is made up of three layers-

A) Diaphragm: pectin-like in like material and rich in lignin, it is very hard And strong.

B) Primary cell wall layer: 

   1. Made of pectin, cellulose, hemicellulose, and polysaccharides.

   2. Protoplasmic pores located in the cell wall  Cells form connections between adjacent cells, called cell Plasmodesmata. (singular plasmodesma).

   3. It helps transport chemicals and water in cells.

C) Secondary cell wall layer: It is formed on the first layer. This layer again has three layers inside, inside, and outside.

1. Cell size and stress tolerance are mainly dependent on this layer.

2. Chemical composition:

•The cell membrane is usually composed of cellulose, polysaccharides etc.4

•Cellulose, lignin, pectin etc. released from protoplasm are accumulated to form the primary cell wall.

•The secondary cell wall is composed of cutin, suberin, wax, calcium oxalate and various inorganic salts.

Microscopic Structure of cell wall: 

The structure cell wall is discussed below.

Primary Cell Wall Structure:

1st stage:

•How many long-chain cellulose molecules are present in the cell wall at the smallest visible level? Cellulose molecules are polymers of about 3,000 units of glucose.

•These cellulose molecules are arranged in parallel and connected with each other to form mycelium or primary cellulose molecules like twisted threads or ribbons.

•Maximum diameter of each mycelium is 100Å or 10nm and the cross-section it shows about 100 cellulose fibers.

2nd Stage:

•It has many mycelia (about 20) re-arranged in parallel to microfibrils-like bundles.

•Microfibrils are 25 nm in diameter and each microfibril contains about 200 cellulose units.

3rd Stage:

•Many of these 250 microfibrils reassemble into bundle-like microfibrils or complete cellulose fibers.

•The diameter of is about 0.4µm. [1 micrometer  = 1000 nanometer].  Each microfibril contains about 50,000 cellulose molecules. These are the basic building blocks of the primary cell wall.

Secondary or secondary cell wall structure:

•The secondary cell wall is composed of polymers of cellulose, pectin, non-cellulosic polysaccharides, hemicellulose, lignin, and phenolics.

• Non-cellulose polysaccharides include the sugars arabinose, xylose, mannose and galactose.

•Cellulose present in the secondary wall is more tightly packed with macrmicrofibrils like  the primary layer.

The function of the cell wall:

1. Cell wall gives proper shape to the cell.

2. Protects protoplasm from external adverse conditions.

3. Provides the cells with the required rigidity.

4. Regulates movement of mineral salts in and out of cells.

5. Cell junctions are protected with the help of plasmodesmata.

Conclusion:

The cell wall, which offers structural support and security, is a crucial component of plant cells. The regulation of water and nutrient absorption, as well as plant protection against pathogens and environmental duress, are all important functions of the cell wall. Research into the cell wall is crucial because it has the potential to progress biotechnology, agribusiness, and health.