To classify bacteria in two groups using the Gram stain certain things must be known. The prokaryotic shape and amount of peptidoglycan all come into play.
Prokaryotic organisms are thought to be the first organisms on earth. Mostly unicellular their most known shapes are the three following: speheres or cocci, bacilli or rods, and spirals. Cocci usually come in pairs and are joined together in a line. Bacilli on the other hand, have oval shaped bodies like rods. Lastly the spiral shaped prokaryotes may be up to 5 um long.
However despite their appearance prokaryotics have a complex system of structures. Their cell walls are used to keep the cell’s shape and prevent it from brusting during hypotonic situtations. Another key freture that the cell wall does is that it gives physical protection. These bacertial cells have peptidoglycan which are modified- sugar polymers crosslinked by short polpypeptides, which surrounded the bacteria. While Archaeal cells have polysaccharides and protiends instead of peptidoglycan.
The Gram stain is what has been used to calissify these bacteria, apart from their shape. The classification system takes it’s place by cell wall composition. Gram – positive bacteria will contain less complex cell walls with peptidoglycan increasingy present. While Gram- negative bacterial will be the oppiste. They will have an oppiste result of little peptidoglycan amounts along with the outer membrane having lipoplysaccharides.
In the process of Gram staining the bacteria in question are stained using crystal violet dyd with iodine, afterwhich they are then rinsed with alchol and then stained again using red dye. Weather it has large peptidoglycan amounts or small peptidoglycan amounts is what will determine the Gram testing and color of the result.
If the restul is Gram- postive the bacteria will therefore have a more violet color in the cytoplasm. While a Gram- negative bacteria will have a red or pink color in the cytoplasm. In this way bacteria is easily identifiable in two seperate categories. Those with a high amount of peptidoglycan or low amount of peptidoglycan.
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