Biology

Difference Between Gram Positive Bacteria and Gram Negative Bacteria

Main difference

We know that bacteria are an invisible creature that can make us sick, but we know very little that bacteria can also be useful to living organisms as well as being harmful. Mainly, there are seven types of bacteria, which are divided into two main types of bacteria; gram positive bacteria and gram negative bacteria. Danish scientist Hans Christian Gram came up with the idea of ​​differentiating between both types of bacteria by the structural difference of their cell walls and their staining ability when stained with Gram’s stain. The scientist mentioned above devised a laboratory method called ‘Gram stain’ to differentiate between both types of bacteria.In this method, the Gram stain, which is usually the weak alkaline solution of crystal violet, is stained with bacteria. Bacteria that retain the crystal violet stain are identified as Gram positive bacteria, while bacteria that do not retain the violet stain are identified as Gram negative bacteria. Later, when the gram negative bacteria are stained with safranin or fuchsin in the experiment, it gives a red or pink color.

Comparative chart

Gram Positive Bacteria Gram-negative bacteria
Gram stain After undergoing the ‘Gram staining’ process, the bacterium, which retains the crystal violet dye, is identified as Gram Positive bacteria. After undergoing the ‘Gram stain’ process, bacteria that do not retain the violet dye are identified as gram-negative bacteria.
Peptidoglycan Thicker Thinner
Cellular wall Thicker and smoother. Thinner and wavy.

What are gram positive bacteria?

It is one of the main types of bacteria that are identified by a method devised by the Danish scientist Hans Christian Gram. The laboratory method, which distinguishes this type of bacteria from the other famous type of bacteria, is named after the scientist himself, the “Gram stain” method. Bacteria is the prokaryotic organism that is made up of the special layer called peptidoglycan; this layer is thick or thin in size. In Gram positive bacteria, the peptidoglycan layer is thick, so when this type of bacteria is stained with the Gram stain it retains the crystal violet dye. The cell wall of gram-positive bacteria is as thick as the peptidoglycan layer and is smoother compared to the wall of the other famous type of bacteria. In the Gram stain experiment, the bacterial cells are washed with alcohol (bleaching solution) after they are treated with the iodine solution. After this, the bacteria that retain the crystal violet dye are identified as gram-positive bacteria.

What are gram negative bacteria?

It is one of the main types of bacteria that is also identified after it undergoes a standard laboratory experiment called ‘Gram stain’. One of the most notable differences between these types of bacteria and other types of bacteria is that they do not retain the violet tint when washed with alcohol. In the Gram stain experiment, the bacterial cells are washed with alcohol (bleaching solution) after they are treated with the iodine solution. After this, bacteria that do not retain the crystal violet dye are identified as gram-negative bacteria. Later, when the gram negative bacteria are stained with safranin or fuchsin in the experiment, it gives a red or pink color. The reason negative bacteria lose color is that they have the thin layer of peptidoglycan and when staining,

Gram Positive Bacteria vs. Gram Negative Bacteria

  • After undergoing the ‘Gram stain’ process, bacteria that retain crystal violet dye are identified as Gram Positive bacteria, while bacteria that do not retain violet dye are identified as Gram negative.
  • In gram-positive bacteria, the peptidoglycan layer is thick compared to the peptidoglycan layer in gram-negative bacteria.
  • The cell wall of gram-positive bacteria is thicker compared to the cell wall of gram-negative bacteria.
  • The cell wall of gram positive bacteria is smooth, while the cell wall of gram negative bacteria is wavy.
  • When the gram negative bacteria are stained with safranin or fuchsin in the experiment, it gives a red or pink color.

Leave a Reply

Your email address will not be published. Required fields are marked *

Check Also
Close
Back to top button