Bacterial Cell Wall

Cell Wall

The prokaryotic cell’s wall is located outside the plasma membrane and gives the cell its

shape, providing rigid structural support for the cell. The cell wall also protects the cell

from its environment.

Pressure within the cells builds as fluid containing nutrients enters the cells. It is the job

of the cell wall to resist the pressure the same way that the walls of a balloon resist the

build-up pressure whan it is inflated. If pressure inside the cell becomes too great, the cell

wall bursts, which is referred to as lysis.

The cell wall of many bacteria is composed of peptidoglycan, which covers the entire

surface of the cell. Peptidoglycan is made up of a combination of peptide bonds and

carbohydrates, either N-acetylmuramic acid, commonly referred to as NAM, or Nacetylglycosamine,

which is known as NAG

The wall of a bacterium is classified in two ways:

Gram-positive: A gram-positive cell wall has many layers of Peptidoglycan that retain

crystal violet dye when the cell is stained. This gives the cell a purple color when seen

under a microscope

Gram-negative: A gram negative cell wall is thin. The inside is made of Peptidoglycan.

The outer membrane is composed of phospholipids and lipopolysaccarides. The cell wall

does not retain the crystal violet dye when the cell is stained. The cell appears pink when

view with a microscope.