|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?
- Organism 1 is Gram-positive and is unable to ferment glucose.
- Organism 2 is Gram-negative and can ferment sucrose.
- Organism 3 is Gram-negative and can ferment lactose*.
- All three organisms are Gram-negative and can ferment sucrose.
- None of the above conclusions are correct.
2. The product shown in the image here is used to identify
- Gram-positive cocci.
- Gram-negative cocci.
- Gram-positive bacilli .
- Gram-negative bacilli. *
- Gram-positive spirochetes.
3. Staphylococcus aureus , a major pathogen, is usually
- alpha hemolytic.
- beta hemolytic. *
- gamma hemolytic.
- delta hemolytic.
- 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
- capable of degrading gelatin. *
- incapable of degrading gelatin.
- capable of clotting plasma.
- incapable of clotting plasma .
- 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
- Voges-Proskauer positive.
- Voges-Proskauer negative.
- indole positive. *
- indole negative.
- methyl red positive.
6. The bacteria that produced the result shown at the arrow in this image
- produce very acid products from glucose.
- produce somewhat alkaline products from glucose.
- produce indole when it degrading trptophan.
- do not produce indole when degrading trptophan.
- 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
- able to ferment mannitol and probably is Staphylococcus epidermidis.
- able to ferment mannitol and probably is Staphylococcus aureus.
- unable to ferment mannitol and probably is Staphylococcus epidermidis .*
- unable to ferment mannitol and probably is Staphylococcus aureus.
- 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
- is motile and possesses flagella. *
- is nonmotile and lacks flagella.
- is motile and lacks flagella.
- is nonmotile and possesses flagella.
9. Methyl red test results for different organisms are shown in this image. Which conclusion is correct?
- Tube 1 indicates an acidic pH as a result of fermentation of lactose.
- Tube 2 indicates an acidic pH as a result of fermentation of lactose.
- Tube 1 indicates an acidic pH as a result of fermentation of glucose.
- Tube 2 indicates an acidic pH as a result of fermentation of glucose. *
- None of the above are correct conclusions for these results.
10. Pathogens that are usually beta-hemolytic include
- Staphylococcus aureus.
- Streptococcus pyogenes (Group A Strep).
- Streptococcus pneumoniae.
- a and b only *
- a, b and c