Acid-Fast Stains quiz

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Acid-Fast Stains quiz
2013-10-22 23:49:33
Lab quiz

Acid-Fast Stains quiz
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  1. What is the significance of mycolic acids in the cell walls of acid-fast organisms?
    It is the cytological basis for the acid-fast differential stain.

    It is a waxy substance that gives acid-fast cells a higher affinity for the primary stain and resistance to decolorization by an acid alcohol solution.
  2. What are the two methods of the acid-fast staining?
    • Niehl-Neelsen
    • Kinyoun method
  3. What is the difference between the Ziehl-Neelsen and the Kinyoun methods?
    Ziehl-Neelson method uses heat as part of the staining method and the Kinyoun method is a cold stain.
  4. What is the significance of the serum?
    It helps the slippery acid-fast cells adhere to the slide.
  5. What is the significance of the waxy wall of acid-fast cells?
    repels typical aqueous stains.
  6. What is the Ziehl-Neelson method primary stain?

    What odes it do?
    It is a phenolic compound.

    • Phenolic compound carbolfuchsin is a lipid-soluble and penetrates the waxy cell wall.
    • and stains acid-fast negative cells
  7. How is carbolfuchsin further enhanced?

    What happens when the wax is melted?
    by steam-heating the preparation to melt the wax and allow the stain to move into the cell.

    the stain moves into the cell.
  8. A methylene blue is applied, what color do the cells turn?

    What color do nonacid-fast cells turn?

    color of the counterstain.
  9. What kind of a primary stain does the Kinyoun method use?

    Why is that used?
    a more soluble lipid-soluble stain.

    Allows the stain to penetrate the acid-fast walls without the use of heat and makes it slightly less sensitive than the an mthod.
  10. In the Kinyoun method, what follows the primary stain of the more lipid soluble and concentrated carbolfuchsin step?
    Decolorization with acid alcohol and a counterstian using either brilliant green or methylene blue.