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Why is it important to include both gram negative and gram negative organisms in a smear prep when you are performing the gram stain?
The point of the gram stain is to differentiate between two things, with out both positive and negative gram cells there would be nothing to differentiate between, defeating the purpose of the process.
Why is decolorization necessary when performing a gram stain?
During the procedures of a gram stain, decolorization is necessary to remove any stain or color from the gram negative cells. When a dye is used to stain gram positive cells, both gram positive and gram negative cells retain color. Mordant is used to bind the original stain to gram positive cells so when decolorizer is used they retain color. After the mordant has been used a decolorizer is used to wash away colo in gram negative cells. Counterstains are used to stain gram negative cells to better visualize contrasting cells. An example of a decolorizer that works well is ethanol.
What color are gram negative cells?
Gram positive bacterial stain purple. They do not take up the counter stain.
Which step in the gram stain is the critical step in differentiating gram positive cells from gram negative cells?
Alcohol-acetone
Why does the counterstain not change the color of all of the cells is it because the primary stain repels or masks the secondary stain?
In a gram stain the primary stain is crystal violet. Iodine then sets that dye into the gram positive cells while alcohol washes out the crystal violet from the gram negative cells. Then safranin, which is the counterstain in a gram stain, is used to dye the rest of the bacteria. This is the example I can give you of why a counterstain does not change the look in all the cells. Though safranin stains all the cells, the gram positive cells that were dyed purple from crystal violet don't look pink - only the gram negative do.
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.
Why is it important to include both gram negative and gram negative organisms in a smear prep when you are performing the gram stain?
The point of the gram stain is to differentiate between two things, with out both positive and negative gram cells there would be nothing to differentiate between, defeating the purpose of the process.
Why is decolorization necessary when performing a gram stain?
During the procedures of a gram stain, decolorization is necessary to remove any stain or color from the gram negative cells. When a dye is used to stain gram positive cells, both gram positive and gram negative cells retain color. Mordant is used to bind the original stain to gram positive cells so when decolorizer is used they retain color. After the mordant has been used a decolorizer is used to wash away colo in gram negative cells. Counterstains are used to stain gram negative cells to better visualize contrasting cells. An example of a decolorizer that works well is ethanol.
Why will gram positive cells stain gram negative?
Contamination
What color are gram negative cells?
Gram positive bacterial stain purple. They do not take up the counter stain.
Which step in the gram stain is the critical step in differentiating gram positive cells from gram negative cells?
Alcohol-acetone
Why does the counterstain not change the color of all of the cells is it because the primary stain repels or masks the secondary stain?
In a gram stain the primary stain is crystal violet. Iodine then sets that dye into the gram positive cells while alcohol washes out the crystal violet from the gram negative cells. Then safranin, which is the counterstain in a gram stain, is used to dye the rest of the bacteria. This is the example I can give you of why a counterstain does not change the look in all the cells. Though safranin stains all the cells, the gram positive cells that were dyed purple from crystal violet don't look pink - only the gram negative do.
If Gram positive cells are not decolonize what color would they appear after completing the Gram stain?
pink
Purpose of decolorizing agent?
The decolorizer, usually acetone or alcohol, is used to wash the Crystal Violet stain from the Gram Negative cells. From this point Safranin stain is used to stain the Gram Negative cells. The final color for Gram Negative will be a Red/Pink color.
Does the gram stain procedure work for all bacteria?
Yes. The gram stain procedure separates all bacteria into one of two groups - into gram-negative bacteria which do not stain purple and into gram-positive cells which do stain purple. In structural terms, the ability of a cell to become stained during the gram stain procedure is due to the chemical makeup of the cell wall.
What is the current theory about the mechanism of the gram stain?
The gram stain is a basic differential stain used to determine if a bacterial cell is gram positive or negative. Gram positive cells have a thick peptidoglycan layer that will trap the crystal violet iodine crystalls and apear purple. Gram negative cells only have a thin peptidoglycan layer that allows the crystals to diffuse out of the cell and will only be seen with the application of a counterstain, such as safranin which turns the cells pink.
Can you gram stain a cell without a cell wall?
No bacteria exist without a cell wall! If they loose cell wall then they die. Gram staining is used to differentiate gram positive (that doesnt have outer membrane) and gram negative (cell wall+outer membrane) bacteria.
