1. Upon performing a nitrate test, you observe the following: No gas in the Durham tube, sediment, and after addition of the nitrate reagents A & B, the media remained clear/yellow. The next step would be to add __ to the tube.

A. Bacteria
B. Zinc
C. Oxidase reagent
D. Kovacs reagent
2. If the nitrate tube turns red after the addition of zinc, what do these results tell you?

A. Bacteria are fermenters
B. Bacteria are only able to reduce nitrate to nitrite
C. Bacteria are able to reduce nitrate to nitrous oxide/nitrogen gas
D. Bacteria are not able to reduce nitrate
3. The citrate test is performed to see if bacteria can ferment citrate as its sole carbon source. Which of the following changes in the media identify a positive result? (check all that apply)
a. drop in pH
b. color change from blue to green
c. a rise in pH
d. a color change from green to blue
4. The presence of indole can be determined using a MIO tube. Which tube is used to test for indole?

A. MIO tube with oil
B. MIO tube without oil
5. How can you determine if indole was produced? (Identify a positive result). What does a positive indole result mean?
6. What follows is a fill in the blank question with 2 blanks.
In the (name the test) test bacteria that produce a negative result will not grow. This test is considered _ and is able to isolate bacteria that produce a positive result.
7. How can you tell if starch in the media was hydrolyzed by the bacterial colony? (be specific)
Name the enzyme responsible for the hydrolysis of starch.
8. After inoculation and incubation, what are the colors of the OF Glucose tubes for fermenters, oxidizers and neither? Label your answers with the letters a-f.

Color of Aerobic tube Color of Anaerobic tube
Fermenter a. b.
Neither c. d.
Oxidizer e._ f.__

9. What does the oxidase test detect in bacteria?

A. The oxidase test detects the presence of a protein in glycolysis
B. The oxidase test detects the presence of Oxygen
C. The oxidase test detects pyruvate, a molecule entering the Krebs cycle
D. The oxidase test detects the presence of cytochrome C, a molecule in the electron transport chain

10. A sucrose (glucose + fructose) fermentation tube containing 1% sucrose and peptone was inoculated with bacteria X. After 24 hours of incubation, the tube changed from orange to yellow. No bubble was observed in the Durham tube. What can you conclude from the results? (check all that apply)
A. Acids were produced in the fermentation tube
B. Oxygen was produced in the tube
C. Bacteria X will be able to ferment glucose
D. Bacteria X use peptone in the media as the energy source
11. What follows is a fill in the blank question with 2 blanks.
Bacteria that bubble when H2O2 (hydrogen peroxide) is dropped onto them is said to have the _ enzyme (name the enzyme). What are the bubbles (what kind of gas)? _______
12. What is the reason for adding mineral oil to the MIO tube after it was inoculated with bacteria (what is the purpose)?

A. to create a basic environment which is a positive result
B. to create an environmental condition that will allow the organism to decarboxylate the ornithine
C. to see if the organism can ferment the glucose
D. to see if the organism can oxidize the glucose
13. Two peptone iron deeps were inoculated with bacteria X and bacteria Y respectively. After 24 hours, both test tubes show growth and the tube with bacteria X shows a black precipitate in the bottom of the tube. The tube with Bacteria Y shows no change in color. Identify the black precipitate and explain how it forms (where did it come from)? (be specific and explain the reaction)

14. Bacteria A were inoculated into 2 OF glucose tubes and oil was placed into one of the tubes. After incubation, the aerobic tube turned blue, and the anaerobic tube remained green. The same bacteria were inoculated into a lactose broth containing 1% lactose and peptone. After incubation, what results would you expect to see?

A. The lactose broth will turn yellow, indicating that Bacteria A are able to ferment lactose
B. The lactose broth will turn pink, indicating that Bacteria A are able to ferment lactose
C. The lactose broth will turn yellow, indicating that Bacteria A use lactose oxidatively
D. The lactose broth will turn pink, indicating that Bacteria A are unable to ferment lactose, but used peptone instead

Question

mAstAhLEE mAstAhLEE

26-10-2022
Biology

Answered

1. Upon performing a nitrate test, you observe the following: No gas in the Durham tube, sediment, and after addition of the nitrate reagents A & B, the media remained clear/yellow. The next step would be to add __ to the tube.

A. Bacteria
B. Zinc
C. Oxidase reagent
D. Kovacs reagent
2. If the nitrate tube turns red after the addition of zinc, what do these results tell you?

A. Bacteria are fermenters
B. Bacteria are only able to reduce nitrate to nitrite
C. Bacteria are able to reduce nitrate to nitrous oxide/nitrogen gas
D. Bacteria are not able to reduce nitrate
3. The citrate test is performed to see if bacteria can ferment citrate as its sole carbon source. Which of the following changes in the media identify a positive result? (check all that apply)
a. drop in pH
b. color change from blue to green
c. a rise in pH
d. a color change from green to blue
4. The presence of indole can be determined using a MIO tube. Which tube is used to test for indole?

A. MIO tube with oil
B. MIO tube without oil
5. How can you determine if indole was produced? (Identify a positive result). What does a positive indole result mean?
6. What follows is a fill in the blank question with 2 blanks.
In the (name the test) test bacteria that produce a negative result will not grow. This test is considered _ and is able to isolate bacteria that produce a positive result.
7. How can you tell if starch in the media was hydrolyzed by the bacterial colony? (be specific)
Name the enzyme responsible for the hydrolysis of starch.
8. After inoculation and incubation, what are the colors of the OF Glucose tubes for fermenters, oxidizers and neither? Label your answers with the letters a-f.

Color of Aerobic tube Color of Anaerobic tube
Fermenter a. b.
Neither c. d.
Oxidizer e._ f.__

9. What does the oxidase test detect in bacteria?

A. The oxidase test detects the presence of a protein in glycolysis
B. The oxidase test detects the presence of Oxygen
C. The oxidase test detects pyruvate, a molecule entering the Krebs cycle
D. The oxidase test detects the presence of cytochrome C, a molecule in the electron transport chain

10. A sucrose (glucose + fructose) fermentation tube containing 1% sucrose and peptone was inoculated with bacteria X. After 24 hours of incubation, the tube changed from orange to yellow. No bubble was observed in the Durham tube. What can you conclude from the results? (check all that apply)
A. Acids were produced in the fermentation tube
B. Oxygen was produced in the tube
C. Bacteria X will be able to ferment glucose
D. Bacteria X use peptone in the media as the energy source
11. What follows is a fill in the blank question with 2 blanks.
Bacteria that bubble when H2O2 (hydrogen peroxide) is dropped onto them is said to have the _ enzyme (name the enzyme). What are the bubbles (what kind of gas)? _______
12. What is the reason for adding mineral oil to the MIO tube after it was inoculated with bacteria (what is the purpose)?

A. to create a basic environment which is a positive result
B. to create an environmental condition that will allow the organism to decarboxylate the ornithine
C. to see if the organism can ferment the glucose
D. to see if the organism can oxidize the glucose
13. Two peptone iron deeps were inoculated with bacteria X and bacteria Y respectively. After 24 hours, both test tubes show growth and the tube with bacteria X shows a black precipitate in the bottom of the tube. The tube with Bacteria Y shows no change in color. Identify the black precipitate and explain how it forms (where did it come from)? (be specific and explain the reaction)

14. Bacteria A were inoculated into 2 OF glucose tubes and oil was placed into one of the tubes. After incubation, the aerobic tube turned blue, and the anaerobic tube remained green. The same bacteria were inoculated into a lactose broth containing 1% lactose and peptone. After incubation, what results would you expect to see?

A. The lactose broth will turn yellow, indicating that Bacteria A are able to ferment lactose
B. The lactose broth will turn pink, indicating that Bacteria A are able to ferment lactose
C. The lactose broth will turn yellow, indicating that Bacteria A use lactose oxidatively
D. The lactose broth will turn pink, indicating that Bacteria A are unable to ferment lactose, but used peptone instead

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