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Function of Gram's iodine?
Gram's iodine is used in the Gram staining method to differentiate bacteria into two major groups: Gram-positive and Gram-negative. It functions by forming complexes with the crystal violet dye in the cell wall of the bacteria. This allows for the retention of the dye by Gram-positive bacteria, while it is washed off from Gram-negative bacteria.
What color will gram positive cells become if you fail to use iodine?
Gram positive cells will appear pink if iodine is not used in the Gram staining process. This is because without iodine, the crystal violet stain is not retained by the thick peptidoglycan layer of the cell wall in Gram positive bacteria.
What is the staining process for separating bacteria?
One common staining process for separating bacteria is the Gram staining method. This involves applying crystal violet, iodine, alcohol, and safranin to the bacterial sample. Gram-positive bacteria will retain the crystal violet stain, appearing purple, while Gram-negative bacteria will not retain it and will appear pink after the safranin counterstain.
What is the mordant in a gram stain?
Gram's iodine stain is applied after the culture is stained with the primary stain. It acts as a mordant, fixing the primary stain to the cell wall while lending no additional colour to the cell (i.e. the mordant itself is not a stain). The mordant is only able to fix the stain to Gram-positive bacteria because of the characteristic thick, peptidoglycan coat that they possess. Because the mordant is not able to fix the stain to Gram-negative bacteria (who's coat have a different composition), the crystal violet stain will wash away from Gram-negative bacteria when the decolourizing agent is added.
Is gram staining related to flagella?
No, gram staining and flagella are not directly related. Gram staining is a technique used to classify bacteria based on cell wall characteristics, while flagella are thread-like appendages that help bacteria move. Flagella presence or absence does not affect the results of a gram stain.
