Bacteria cell wall is an important structure for bacteria.
For man it is also important as a clinical target.
Cell wall is the immediate structure adjacent to cell membrane. It is an outer most layer.
Because of cell wall bacteria survives in the most severe conditions like drought, heat, chemical exposure etc.
Thus cell wall is an important structure which keeps it immortal.
The cell wall is a characteristic feature similar to plant. So, some scientists even classify it under plant kingdom. But unlike plants, the contents of the wall are quite different.
The bacterial cell wall is tough, rigid with specific shape.
The bacterial cell wall structure:
Structure of bacterial cell wall is classified into two types. The one present in gram positive bacteria and the other present in gram negative bacteria. Below you can see the images for structures of two cell walls.
Gram positive bacteria cell wall:
This cell wall is very rigid and is made largely of peptidoglycon. Peptidoglycon is a combination of protein and carbohydrate molecules.
Because of this high amount of peptidoglycon layer, the bacteria show blue color when stained with gram stain. The layer does not take up saffron color of stain unlike gram negative bacteria. This difference in cell wall structure makes the bacteria susceptible to antibiotics which act on the cell wall.
Gram Negative bacteria cell wall:
This cell wall is quite different to the one above. The amount of peptidoglycon layer is very much low.
Besides it also has lipoproteins, lipopolysaccharides, phospholipds techoic acid etc. This cell wall when stained with grams stain, it attain saffron color. The lipopolysaccharide layer hold the saffron dye in the stain and is responsible for the color.
Functions of bacteria cell wall:
- It helps to provide fixed shape to the cell.
- It facilitates movement of gases and water into and outside the cell.
- It prevents from the cell getting dried.
- It protects from chemicals and other harsh condition of environment. Hence we use heat sterilization to kill bacteria.
- The outer most layer also called S-layer helps the bacteria to escape from phaogocytosis by host immune cells.
Because of the cell wall presence humans target them by giving drugs (antibiotics) which destroy cell wall. Since human cells don’t have a wall, they are unaffected. Similarly due to difference in gram +ve and gram -ve bacteria, a antibiotic with specificity to one type of bacteria can be given. Thus presence of bacteria is good for bacteria but also provides a safe option for human health care.