micro lab exam 1

  1. Predict the result of the following “mistake” made when performing a Gram stain. Reversal of crystal violet and safranin stains




    B. gram negative cells would look like gram positives
  2. What is the name of the primary stain used in a gram stain?




    B. crystal violet
  3. What is a negative stain?




    C. a stain that colors the background rather than the cell
  4. When is it appropriate to ask the laboratory to perform an acid-fast stain?




    A. when an acid fast organism is suspected
  5. What is the function of the iodine in a gram stain?




    C. it holds the primary stain in gram positives
  6. What is the advantage of the gram stain over the simple stain?




    B.  it identifies the cell wall structure
  7. Predict the result of the following “mistake” made when performing a Gram stain.

    Failure to apply the counterstain




    A. some cells would be transparent while some would appear gram-positive
  8. Predict the result of the following “mistake” made when performing a Gram stain. 

    Failure to apply the alcohol solution




    A. all cells would appear gram positive
  9. What is the purpose of the alcohol solution in a gram stain?




    B. it removes the primary stain
  10. In the acid-fast staining procedure, why is carbolfuchsin used as a primary stain?




    B. it can penetrate the waxy-lipid cell wall
  11. Name the three locations that a spore may be found within a vegetative cell. (Select all that apply)

    A. terminal
    B. central
    C. subterminal
    • A. terminal 
    • B. central 
    • C. subterminal
  12. Why is a Gram stain not an adequate substitute for an acid-fast stain?

    gram staining cannot penetrate cell walls with mycolic acid in them
    gram staining cannot penetrate cell walls with mycolic acid in them
  13. What does the mordant do in a flagella stain?

    it makes the flagellum thick enough to see
    it makes the flagellum thick enough to see
  14. What is a pure culture?

    A: colony that contains only one species of bacterium
    A: colony that contains only one species of bacterium
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micro lab exam 1
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odessa college micro lab 1 flash card
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