Question

For each type of cell wall in bacteria (gram positive vs. gram negative ) describe the unique components present in each and list how each layer of the cell wall is connected together ( what molecules accomplish this)?

Answer 1

Gram-negative bacteria are characterized by their inability to retain crystal violet stain, which is used to differentiate gram-positive and gram-negative bacteria. The layers of the gram-negative cell wall include,

• The inner cytoplasmic membrane
• Middle peptidoglycan layer
• Outer lipopolysaccharide layer
• The S-layer attached to the outer layer

The outer layer helps the bacteria to other cells or organisms and infects them. The middle peptidoglycan layer is sandwiched between the inner layer and the outer layer, which is very thin to retain the crystal violet stain. The outer layer contains porins that act as channels for molecules. The cell membrane also provides structural integrity for the bacteria. The proteins, vitamins, amino acids and enzymes embedded in the bacterial membrane provide the essential nutrients for the bacterial growth.

The three layers of the gram-positive cell wall include,

• The inner cytoplasmic membrane
• Middle peptidoglycan layer
• The S-layer attached to the outer layer

The Gram-positive bacteria do not contain the outer lipid layer, but their peptidoglycan layer is thick, which retain the Crystal violet stain. Thus, Gram, bacteria are more susceptible to antibiotics.