객관식
In a standard Gram stain, what color do Gram-negative bacteria typically appear after the safranin counterstain is applied?
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9. Microscopes
Gram Stain
객관식
Which of the following statements is false?
A
Crystal violet is used to stain the cells purple.
B
Alcohol is used to kill the bacteria that are not stained.
C
Gram positive cells end up being stained purple.
D
Iodine is used to affix the crystal violet dye to gram positive cells.
검증된 단계별 안내1
Understand the Gram staining process, which is a differential staining technique used to classify bacteria into Gram-positive and Gram-negative based on the properties of their cell walls.
Recognize that crystal violet is the primary stain used in the Gram staining process, which initially stains all cells purple.
Know that iodine is used as a mordant in the Gram staining process. It forms a complex with crystal violet, helping to fix the dye within the thick peptidoglycan layer of Gram-positive bacteria.
Identify that alcohol or acetone is used as a decolorizing agent in the Gram staining process. It dehydrates the peptidoglycan layer, shrinking and tightening it, which helps retain the crystal violet-iodine complex in Gram-positive cells, while Gram-negative cells lose the dye.
Evaluate the statement 'Alcohol is used to kill the bacteria that are not stained.' This is incorrect because the primary role of alcohol in the Gram staining process is to act as a decolorizer, not to kill bacteria.
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