Question

NAME________________ 9. How would you interpret the following: Turbidity throughout the tube and a pink color after adding the Kovac's reagent. Mark all that apply. a. The bacterium is motile. d. The bacterium produces acid. b. The bacterium degrades tryptophan. e. The bacterium reduces sulfur. c. This is a negative result. Triple Sugar Iron [TSI] agar 10. In the TSI agar test, glucose is in limited supply whereas 10 times the amount of sucrose and lactose are provided [compared to the amount of glucose]. If a bacterium can only ferment glucose but not sucrose or lactose, it will consume all the glucose and then degrade the protein in the agar. Which of the following results would you expect? a. Yellow slant and yellow butt end d. Yellow slant and pink/red butt end. b. Pink/red slant and pink/red butt end. e. All these apply. c. Pink/red slant and yellow butt end. 11. In the TSI agar test, you observe growth and the slant and butt end are red/pink. What, if anything, can you conclude about this bacterium? a. Bacteria died because they were unable to use citrate as a carbon source. b. The bacteria are not members of Enterobacteriaceae because glucose was not fermented. c. This is a false positive test; too many bacteria were used to inoculate. d. Bacteria fermented glucose, sucrose and/or lactose. e. Lactose fermentation indicates bacteria are coliform. 12. When analyzing your results, you notice that the butt end of the agar has been disturbed - that is, it has lifted off the bottom of the glass tube. In addition, both the slant and butt end are yellow. These results indicate... a. Bacterium did not ferment the sugar. d. Bacterium produced gas during fermentation of the sugars. b. Bacterium degraded protein. e. This is an example of reversion. c. This test is inconclusive for gas production. 13. Given the results presented in question 12, is it possible that this is a false positive? Assume there was no chance of contamination. a. No; the tube turns yellow only if bacteria have the ability to degrade that particular amino acid. b. No; the tube turns yellow only if bacteria have the ability to degrade the sugars and has produced gas. c. Yes; the bacterium can degrade the other dead bacteria if too much bacteria were used when inoculating. d. Yes; there are any number of reasons why the tube turned yellow. Multiple energy sources are in the tube and the bacterium could have fermented those. Blood Agar Plate 14. You inoculate a BAP with a swab from your throat. You observe a yellow halo or clearing around punctiform [very tiny], white colonies. What conclusions can you make? a. This is an example of alpha hemolysis indicating the microbe makes a weak hemolysin. b. This is an example of gamma hemolysis indicating the microbe makes a strong hemolysin. c. This is an example of beta hemolysis indicating the microbe makes a weak hemolysin. d. This is an example of gamma hemolysis indicating the microbe makes a weak hemolysin. e. This is an example of beta hemolysis indicating the microbe makes a strong hemolysin. 15. We have inoculated media containing blood twice this semester. The second time, the medium did not contain phenyl ethyl alcohol. As a result... a. These plates are not differential. d. This test only allows Gram positive bacteria to grow. b. This test is differential only. e. This test is selective only. c. There is no difference with the type of results one would get with or without PEA.

          NAME________________
9. How would you interpret the following: Turbidity throughout the tube and a pink color after adding the Kovac's reagent. Mark all that apply.
a. The bacterium is motile.
d. The bacterium produces acid.
b. The bacterium degrades tryptophan.
e. The bacterium reduces sulfur.
c. This is a negative result.

Triple Sugar Iron [TSI] agar
10. In the TSI agar test, glucose is in limited supply whereas 10 times the amount of sucrose and lactose are provided [compared to the amount of glucose]. If a bacterium can only ferment glucose but not sucrose or lactose, it will consume all the glucose and then degrade the protein in the agar. Which of the following results would you expect?
a. Yellow slant and yellow butt end
d. Yellow slant and pink/red butt end.
b. Pink/red slant and pink/red butt end.
e. All these apply.
c. Pink/red slant and yellow butt end.

11. In the TSI agar test, you observe growth and the slant and butt end are red/pink. What, if anything, can you conclude about this bacterium?
a. Bacteria died because they were unable to use citrate as a carbon source.
b. The bacteria are not members of Enterobacteriaceae because glucose was not fermented.
c. This is a false positive test; too many bacteria were used to inoculate.
d. Bacteria fermented glucose, sucrose and/or lactose.
e. Lactose fermentation indicates bacteria are coliform.

12. When analyzing your results, you notice that the butt end of the agar has been disturbed - that is, it has lifted off the bottom of the glass tube. In addition, both the slant and butt end are yellow. These results indicate...
a. Bacterium did not ferment the sugar.
d. Bacterium produced gas during fermentation of the sugars.
b. Bacterium degraded protein.
e. This is an example of reversion.
c. This test is inconclusive for gas production.

13. Given the results presented in question 12, is it possible that this is a false positive? Assume there was no chance of contamination.
a. No; the tube turns yellow only if bacteria have the ability to degrade that particular amino acid.
b. No; the tube turns yellow only if bacteria have the ability to degrade the sugars and has produced gas.
c. Yes; the bacterium can degrade the other dead bacteria if too much bacteria were used when inoculating.
d. Yes; there are any number of reasons why the tube turned yellow. Multiple energy sources are in the tube and the bacterium could have fermented those.

Blood Agar Plate
14. You inoculate a BAP with a swab from your throat. You observe a yellow halo or clearing around punctiform [very tiny], white colonies. What conclusions can you make?
a. This is an example of alpha hemolysis indicating the microbe makes a weak hemolysin.
b. This is an example of gamma hemolysis indicating the microbe makes a strong hemolysin.
c. This is an example of beta hemolysis indicating the microbe makes a weak hemolysin.
d. This is an example of gamma hemolysis indicating the microbe makes a weak hemolysin.
e. This is an example of beta hemolysis indicating the microbe makes a strong hemolysin.

15. We have inoculated media containing blood twice this semester. The second time, the medium did not contain phenyl ethyl alcohol. As a result...
a. These plates are not differential.
d. This test only allows Gram positive bacteria to grow.
b. This test is differential only.
e. This test is selective only.
c. There is no difference with the type of results one would get with or without PEA.

NAME
9. How would you interpret the following: Turbidity throughout the tube and a pink color after adding the Kovac's reagent. Mark all that apply.
a. The bacterium is motile.
d. The bacterium produces acid.
b. The bacterium degrades tryptophan.
e. The bacterium reduces sulfur.
c. This is a negative result.

Triple Sugar Iron [TSI] agar
10. In the TSI agar test, glucose is in limited supply whereas 10 times the amount of sucrose and lactose are provided [compared to the amount of glucose]. If a bacterium can only ferment glucose but not sucrose or lactose, it will consume all the glucose and then degrade the protein in the agar. Which of the following results would you expect?
a. Yellow slant and yellow butt end
d. Yellow slant and pink/red butt end.
b. Pink/red slant and pink/red butt end.
e. All these apply.
c. Pink/red slant and yellow butt end.

11. In the TSI agar test, you observe growth and the slant and butt end are red/pink. What, if anything, can you conclude about this bacterium?
a. Bacteria died because they were unable to use citrate as a carbon source.
b. The bacteria are not members of Enterobacteriaceae because glucose was not fermented.
c. This is a false positive test; too many bacteria were used to inoculate.
d. Bacteria fermented glucose, sucrose and/or lactose.
e. Lactose fermentation indicates bacteria are coliform.

12. When analyzing your results, you notice that the butt end of the agar has been disturbed - that is, it has lifted off the bottom of the glass tube. In addition, both the slant and butt end are yellow. These results indicate...
a. Bacterium did not ferment the sugar.
d. Bacterium produced gas during fermentation of the sugars.
b. Bacterium degraded protein.
e. This is an example of reversion.
c. This test is inconclusive for gas production.

13. Given the results presented in question 12, is it possible that this is a false positive? Assume there was no chance of contamination.
a. No; the tube turns yellow only if bacteria have the ability to degrade that particular amino acid.
b. No; the tube turns yellow only if bacteria have the ability to degrade the sugars and has produced gas.
c. Yes; the bacterium can degrade the other dead bacteria if too much bacteria were used when inoculating.
d. Yes; there are any number of reasons why the tube turned yellow. Multiple energy sources are in the tube and the bacterium could have fermented those.

Blood Agar Plate
14. You inoculate a BAP with a swab from your throat. You observe a yellow halo or clearing around punctiform [very tiny], white colonies. What conclusions can you make?
a. This is an example of alpha hemolysis indicating the microbe makes a weak hemolysin.
b. This is an example of gamma hemolysis indicating the microbe makes a strong hemolysin.
c. This is an example of beta hemolysis indicating the microbe makes a weak hemolysin.
d. This is an example of gamma hemolysis indicating the microbe makes a weak hemolysin.
e. This is an example of beta hemolysis indicating the microbe makes a strong hemolysin.

15. We have inoculated media containing blood twice this semester. The second time, the medium did not contain phenyl ethyl alcohol. As a result...
a. These plates are not differential.
d. This test only allows Gram positive bacteria to grow.
b. This test is differential only.
e. This test is selective only.
c. There is no difference with the type of results one would get with or without PEA.

Added by Andr-S C.

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