MINISTRY OF DEFENCE

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  MINISTRY OF DEFENCE. Establishment Of National University In Islamabad Total position. 29 Domicile , All over Pakistan    Qualification  intermediate to bachelor positions . Project Engineer(Civil) account Officer  supervisor assistant office boy     How to apply.   Apply online through the link https://www.fgei-cg.gov.pk/nup-rec.php   Last date to apply  02 April 2023. No TA/DA Fo Interview 
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Cell Wall

Cell Wall

Cell wall



The outermost boundary in most of the plant cell is cell wall.
It is present in plants, Fungi, bacteria and absent in animals.
Cell walls have different structures and chemical compositions.
Cell wall is non living and secreted by the protoplasm.
Formation of cell wall takes place at telophase of cell division.
       In a young cell, the cell wall is thin and delicate, but in large cell, it becomes thick and strong.
The cell wall consist of three layers.

i) Primary Wall

 It is found around a young plant cell on the outer side of Cell Membrane.
The primary wall is very thin, elastic and capable of great extension.
It consist of cellulose l, hemicellulose, pectin and sugar compounds.
The cellulose molecules are arranged in a criss cross manner.

ii) Secondary Wall:
It is formed on the inner surface of the primary wall.
It is much thick and rigid.
It is composed of inorganic salts, silica, waxes, cutin, lignin, etc

 iii) Middle Lamella:

 It is the layer between two cells.
It helps in the attachment of two cells.
It is composed of calcium pectate.

 (The cell wall of  Bacteria is composed of peptidoglycan and cell wall of fungi composed of chitan).

Functions of Cell Wall:

it gives definite shape to the cell.
2. It provides mechanical supports to the cell.
3. It keeps the cells rigid.
4. It protects the inner contents of cell.
5. All types of materials can pass through it, so it does not act as a barrier for the passing materials.
Cell wall of plant

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