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Multiple Choice
Which of the following staining procedures employs both a primary dye and a counterstain?
A
Negative staining
B
Acid-fast staining
C
Simple staining
D
Gram staining
Verified step by step guidance
1
Understand the purpose of staining in microbiology: Staining is used to enhance the contrast of microscopic organisms, making them more visible under a microscope.
Identify the components of Gram staining: Gram staining involves the use of a primary dye, crystal violet, and a counterstain, safranin.
Learn the process of Gram staining: The procedure starts with the application of crystal violet, followed by iodine treatment, alcohol decolorization, and finally the application of safranin.
Recognize the role of each dye: Crystal violet stains all cells initially, while safranin is used to counterstain cells that have lost the initial dye during decolorization.
Understand the outcome: Gram-positive bacteria retain the crystal violet dye, appearing purple, while Gram-negative bacteria take up the safranin counterstain, appearing pink.