Cell wall introduction


Cell wall introduction

  • Cell wall introduction The cell wall is the outermost part of bacteria fungi and plant cell.
  • In Plant it is composed of cellulose and Hemicellulose, while the bacterial cell wall consist of protein lipid polysaccharide complex.
  • The cell wall is the most important feature of plant, it distinguished them from Animal because Animal are not have cell wall

Cell wall in Bacteria 

  • The outermost boundary of the bacteria or envelope is called cell wall or ECM (Extracellular material) 
  • It is rigid and present outside to the plasma membrane depending upon the constitution of cell wall and their staining reaction bacteria are two types.

1- Gram positive 

  • In gram positive bacteria cell wall is composed of peptidoglycan, (Carbohydrate + Amino Acids) Ex. Bacillus Bacteria

2- Gram Negative 

  • In Gram negative bacteria a second outer lipopolysaccharide layer is located outside the thin peptidoglycan layer.ex. E.Coli.Bacteria

Cell wall in Higher Plant 

  • It is mainly composed of cellulose hemicellulose and pectic acid 
  • Cell wall differ in its composition in different cell type 
  • It is a characteristic feature of the plant cell.
  • It is completely absent in animal cells
  • It is the outermost, non-living thick rigid and porous layer that covers the plasma membrane of the cell.
  • It is secreted by protoplast as a cellulosic fiber on plasma membrane 
  • In young plant cell it is very thin elastic and delicate layer about 1 to 3 µ thick but after the modification by various way it become stiff 5 to 10µ thick as the cell matures.
  • The cell wall of parenchyma tissue cell are comparatively thinner then collenchyma sclerenchyma and xylem and vessels cells.
  • In structure of cell wall two component fibrils and matrix are present which are chemically composed of polysaccharides.
  • The fibrils are made of cellulose and matrix part is made by hemicellulose and pectin substance.
  • During development and modification of cell wall other substance such as protein, lignin, lipids , suberin cutin, resin gum tannins wax etc. are also deposited on cell wall
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