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It allows the primary stain crystal violet to remain in the cell instead of being washed out. Due to the larger size of the crystal violet molecule, when the ethanol is applied (the decolorizer) the stain will not be washed out of the Gram (+) positive cells.
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∙ 12y ago
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∙ 14y agoIodine is often called a "mordant" when used in the gram stain. What its function is, is to form "large" crystals with the Crystal Violet dye used as the first stain. These crystals get trapped in the matrix of the Gram Positive cell walls so when you decolorize the smear properly it won't be washed away from those cells (but will be washed away easily from Gram Negative cells who have the outer membrane surrounding their much thinner cell wall).
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∙ 13y agoThe Gram's iodine serves as a mordant in the Gram stain. It causes the primary stain of crystal violet to more tightly bind to the peptidoglycan in bacterial cell wall of Gram positive bacteria.
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∙ 12y agoGram's Iodine acts as a mordant in gram staining.
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∙ 12y agoit acts as amordant for gram positive bacteria by inhancing the staining of crystal violate
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What is a decolorizer do in gram staining?
It removes the crystal violet (primary stain) from gram negative bacteria. It does not remove Crystal violet as easily from gram positive bacteria, because the highly peptidoglycan walls of gram positive bacteria interact with crystal violet and iodine to form a strong bond (CV-Iodine complex). So, gram positive cells hold on to the stain instead of letting it wash away.
What are the reagents and steps min a Gram stain?
The steps in Gram staining are:1. crystal violet added to the smear2. iodine, the mordant (this fixes the violet)3. a decolorizer made of acetone and alcohol4. safranin, the counterstainIf the cell is Gram +, the decolorizer can not remove the violet. If it is Gram -, the decolorizer can remove the violet and the cell can be then colored with the dye, safranin.Bacteria are grouped in 4 groups by Gram stain:Gram-positive, the cell wall retains crystal Violet.Gram-negative, the cell wall does not retain crystal Violet.Graham not reactive, no staining whatsoever.Graham variable, uneven staining.
Why do all cells stain purple in the flagella stain but not in the gram stain?
The gram stain uses a decolorizing product so it is possible to differentiate between the gram and the gram cells. Gram positive cells stain purple in color.
Theories of principle of gram stain reactions?
Gram stain
If you stain a wet mount of living cells with iodine what are you most likely to see under a microscope?
Starches and (maybe) Gram-positive bacteria.
Why do you use iodine to stain a cell?
Iodine stains starch contained in cells. Iodine is also used to distinguish between Gram negative and Gram positive bacteria. The Gram stain contains iodine.
What is the use of Iodine in gram stains?
The iodine in the gram stain serves as a mordant or fixative.
What function of iodine in gram stain?
fixing the stain so that the first dye which is the crystal violet will not be washed away during rinse process.
What color is gram negative stain and gram positive stain if you forget to apply iodine?
If iodine is not applied, both the gram-positive and gram-negative stains will appear to be gram-negative. The iodine acts as a mordant that helps to fix the crystal violet stain in the gram-positive bacteria, making them appear purple. Without iodine, the crystal violet stain can be easily washed out of both gram-positive and gram-negative bacteria, resulting in a pink or red color.
What function of lugol's iodine in gram staining?
fixing the stain so that the first dye which is the crystal violet will not be washed away during rinse process.
What is the action of iodine in grams stain?
Iodine is used to bind the Crystal Violet to the Gram Positive microbes.
Why is gram's iodine called mordant?
Gram's iodine is called a mordant because it fixes the primary stain to the cell wall and adds any color.
Why gram's iodine called a mordant?
Gram's iodine is called a mordant because it fixes the primary stain to the cell wall and adds any color.
What is the secondary stain in gram stain procedure?
It is crystal violet & stains all cells purple.
What is the difference between gram's stain and wright's stain?
Wright's Stain is a mixture of methylene blue and eosin in methanol. Gram's stain is crystal violet, iodine washed with acetone and proofed with a safranin dye to look for gram negative organism.
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.
Function of iodine in Gram stain?
iodine act as a mordant..on the gram positive bacteria which got really thick and abundence of peptidoglycan layer, the crystal violet will fix to the peptidoglycan layer..meanwhile in gram negative bacteria which is lack of peptidoglycan layer, the alcohol or acetone will wash it away
