Answer Key for Quiz Four:  Biochemical Tests a to c
 
 The correct answer is starred.

1. The arrow in the image shown here identifies a ________ test.

  1. positive catalase
  2. negative catalase
  3. positive coagulase *
  4. negative coagulase
  5. positive hemolysis

2. The organism that produced the result shown at the arrow in question 1 is most likely

  1. Staphylococcus aureus. *
  2. Staphylococcus epidermidis.
  3. Streptococcus pyogenes.
  4. Streptococcus pneumoniae.
  5. Streptococcus mitis.

3. The Kirby-Bauer test is used to determine

  1. which carbohydrates a bacteria can ferment.
  2. if the bacteria can produce gelatinase.
  3. if the organism can produce catalase.
  4. which antibiotics a bacteria is susceptible to. *
  5. the type of hemolysis a bacteria is capable of producing .

4. The arrow in this image indicates an organism that is capable of

  1. degrading gelatin.
  2. being resistant to penicillin.
  3. being sensitive to bacitracin.
  4. clotting plasma.
  5. degrading hydrogen peroxide. *

5. A person with the blood shown in this image has blood type

  1. A.
  2. B.
  3. AB. *
  4. O
  5. all of the above.

6.The bacteria that produced the results shown in this image ferments

  1. glucose only.
  2. lactose only.
  3. sucrose only.
  4. lactose and glucose only. *
  5. lactose and sucrose only.

7. The Interpretive Standards say that a zone of inhibition of 20 mm. qualifies as a sensitive zone for a newly discovered antibiotic. A zone of inhibition of 17 to 19 mm. qualifies as intermediate. If a test bacteria exhibits a 15 mm. zone of inhibition when properly tested against this newly discovered antibiotic on Mueller-Hinton agar, the test organism is most likely to

  1. grow in the presence of the antibiotic. *
  2. die in the presence of the antibiotic.
  3. unable to predict results from the data given.

8. Bacitracin sensitivity is used to distinguish

  1. Streptococcus pneumoniae from other alpha-hemolytic streptococci.
  2. Staphylococcus aureus from Staphylococcus epidermidis.
  3. Staphylococcus from Micrococcus.
  4. Group A Streptococcus from other beta-hemolytic streptococci .*
  5. Group A Streptococcus. from Streptococcus pneumoniae.

9. Sensitivity to bacitracin would best be determined by growing the test organism on

  1. eosin methylene blue agar.
  2. carbohydrate fermentation broth.
  3. blood agar .*
  4. MacConkey agar.
  5. All of the above media would be equally suitable.

10. If the "O" on the disk in this image stands for optochin, what would you conclude about the organism to which the arrow is directed?

  1. The organism is most likely to be Staphylococcus aureus.
  2. The organism is most likely to be Streptococcus pyogenes (Group A Strep). disease
  3. The organism is most likely to be Streptococcus pneumoniae.
  4. The organism is most likely not Streptococcus pyogenes (Group A).
  5. The organism is most likely not Streptococcus pneumoniae *