Answer Key for Quiz Five:  Biochemical Tests e to m
 
 The correct answer is starred.

1. The image here shows three different genera of bacteria growing on EMB agar. They are numbered 1 to 3. Which of the following conclusions is accurate?

  1. Organism 1 is Gram-positive and is unable to ferment glucose.
  2. Organism 2 is Gram-negative and can ferment sucrose.
  3. Organism 3 is Gram-negative and can ferment lactose*.
  4. All three organisms are Gram-negative and can ferment sucrose.
  5. None of the above conclusions are correct.

2. The product shown in the image here is used to identify

  1. Gram-positive cocci.
  2. Gram-negative cocci.
  3. Gram-positive bacilli .
  4. Gram-negative bacilli. *
  5. Gram-positive spirochetes.

3. Staphylococcus aureus , a major pathogen, is usually

  1. alpha hemolytic.
  2. beta hemolytic. *
  3. gamma hemolytic.
  4. delta hemolytic.
  5. incapable of hemolysis.

4. These gelatin tubes have each been inoculated with a pure culture of different bacteria. The tubes were incubated for 48 hours and have been refrigerated for 30 minutes. The arrow in this image indicates an organism that is

  1. capable of degrading gelatin. *
  2. incapable of degrading gelatin.
  3. capable of clotting plasma.
  4. incapable of clotting plasma .
  5. capable of degrading hydrogen peroxide.

5. These tryptone broths were each inoculated with a different bacteria. After incubation Kovac's reagent was added to both tubes. Bacteria that produce the result shown at the arrow in this image are

  1. Voges-Proskauer positive.
  2. Voges-Proskauer negative.
  3. indole positive. *
  4. indole negative.
  5. methyl red positive.

6. The bacteria that produced the result shown at the arrow in this image

  1. produce very acid products from glucose.
  2. produce somewhat alkaline products from glucose.
  3. produce indole when it degrading trptophan.
  4. do not produce indole when degrading trptophan.
  5. are able to utilize citrate as their sole carbon and energy source .*

7. The media shown in this image is mannitol salt agar. The organism that the arrow is pointing to is

  1. able to ferment mannitol and probably is Staphylococcus epidermidis.
  2. able to ferment mannitol and probably is Staphylococcus aureus.
  3. unable to ferment mannitol and probably is Staphylococcus epidermidis .*
  4. unable to ferment mannitol and probably is Staphylococcus aureus.
  5. able to ferment glucose and probably is Staphylococcus aureus.

8. This image shows the results of bacteria inoculated into motility media. The organism in tube 2

  1. is motile and possesses flagella. *
  2. is nonmotile and lacks flagella.
  3. is motile and lacks flagella.
  4. is nonmotile and possesses flagella.

9. Methyl red test results for different organisms are shown in this image. Which conclusion is correct?

  1. Tube 1 indicates an acidic pH as a result of fermentation of lactose.
  2. Tube 2 indicates an acidic pH as a result of fermentation of lactose.
  3. Tube 1 indicates an acidic pH as a result of fermentation of glucose.
  4. Tube 2 indicates an acidic pH as a result of fermentation of glucose. *
  5. None of the above are correct conclusions for these results.

10. Pathogens that are usually beta-hemolytic include

  1. Staphylococcus aureus.
  2. Streptococcus pyogenes (Group A Strep).
  3. Streptococcus pneumoniae.
  4. a and b only *
  5. a, b and c