Cell Wall of Gram Negative Bacteria

Cell wall of Gram negative bacteria

Cell wall of Gram negative bacteria is more rigid and thick then Gram postive bacteria.

It is made up of two layers

1. Peptidoglycan

2. Outer cell wall layer

Component of cell wall of Gram negative cell wall
Component of peptidoglycan of Gram negative cell wall

1. Peptidoglycan

  • It is present in between outer wall layer and cell membrane.
  • The structure is similar as gram positive cell wall.
  • There are some minor differences in the Gram positive and Gram negative peptidoglycan structure.
  • The differences are as follows:-
  1. The third amino acid of tetrapeptide side chainin Gram positive cell wall is L-lysin which is replaced by Mesodiaminopimilic acid in Gram negative cell wall.
  2. All N-acetymuramic acid molecules are not linked to tetrapeptide side chain.
  3. Cross bridges are not made up of glycin molecule they are made up of peptide bond.

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Microbiology – Cell Wall of Gram Positive Bacteria.


  • A bacterial cell shows various parts and these parts have specific structure and functions.
  • These parts are separated by a rigid cell wall some parts are on the internal side of the cell wall and some parts are on the external side of the cell wall.
  • The parts present on the internal side of the cell wall are cell membrane, cytoplasm, nuclear region, reserve food material etc.
  • The cellular parts present on external to the cell wall are flagella, capsule and pilia.

Structure and function of Cell wall

  • The cell wall is the outer covering of bacterial cell in absence of capsule.
  • This cell wall is rigid in nature which imparts a proper shape to bacteria.
  • Cell wall encloses all internal parts of the cell.
  • On the basis of typical structure, composition and Gram staining they are classified

A)   Gram-positive bacteria.

B)   Gram-negative bacteria. Types of bacterial cell

Types of bacterial cell

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Characteristics of Prokaryotic Cells

Characteristics of Prokaryotic Cells

There are two types of cells on the basis of nucleus present within the cell.

1. Prokaryotic cell

2. Eukaryotic cell

1. Characteristics of Prokaryotic cell

Prokaryotic cell
   Prokaryotic cell

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