SSC
BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What is the correct order for gram staining
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Safranin, crystal violet, wash with ethanol, iodine
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Iodine, crystal violet, wash with ethanol, safranin
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Crystal violet, iodine, safranin, wash with ethanol
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Crystal violet, iodine, wash with ethanol, safranin
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Explanation:
Detailed explanation-1: -1) Treatment with 0.5% Iodine solution. 2) Counter staining with safranin. 3) Treatment with absolute ethanol. 4) Staining heat fixed smear with crystal violet.
Detailed explanation-2: -The critical step of the Gram staining procedure is the decolorization step. Hold the slide in a tilted downward position and allow the decolorizer to flow over the smear. Be careful not to miss any portion of the smear. Usually a few seconds will suffice.
Detailed explanation-3: -If you add safranin first and continue the steps for a gram stain would it still not work as the ethanol will remove the purple stain from G-revealing the safranin which it was stained by earlier.
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