Biol 2420 Lab Final Exam Updated Questions And Correct Answers

BIOL 2420 LAB FINAL EXAM UPDATED QUESTIONS AND
CORRECT ANSWERS
Question:
1. what does iodine indi-cate in plate testing?
Answer:
whether the organism produced alpha amylase

Question:
2. what does alpha amy-lase do?
Answer:
hydrolyzes starch to produce many alpha-D-Glucose molecules

Question:
3. what does the enzyme urease do?
Answer:
this enzyme converts urea to ammonia and increases pH drastically

Question:
4. which of the follow-ing media can be used to detect tryptophan degradation to pyru-vate and
indole?
Answer:
SIM

Question:
5. Inoculation of a SIM tube indicates a color change to black. What can be interpreted?
Answer:
sulfur reduction

Question:
6. A bacterium does not reduce nitrate at all. This bacterium is in-oculated in a nitrate broth tube for
24 hours. I add nitrate reagents A and B and, ten minutes later, zinc (reagent C) What should I see?
Answer:
the broth would turn red

Question:
7. Fermentation of the disaccharides lactose and sucrose relied on enzymes to hy-drolyze them into
two monosaccharides. Once these monosac-charides are formed, they are fermented via _______, just
as glucose is.
Answer:
glycolysis

Question:
8. Gas production from fermentation in a phe-nol red broth tube is indicated by the accu-mulation of
gas into a bubble in a _______ tube.

,Answer:
Durham

Question:
9. In a SIM tube, any H2S produced com-bines with _____, in the form of ferrous ammo-nium sulfate
to form ferric sulfide (FeS), a _________ precipitate.
Answer:
Iron; black

Question:
10. Kovac's reagent reacts with ______ to form a _______ product.
Answer:
Indole; red

Question:
11. Your TSI tube had a red slant and a yellow butt. This means that?
Answer:
Glucose fermentation with acid production; proteins catabolized aerobi-cally in the slant with alkaline
reversion products.

Question:
12. You inoculate a cit-rate tube with you un-known. Which of the following indicate cit-rate
utilization?
Answer:
Blue color and no color change but growth of organism on citrate slant

Question:
13. T or F, A positive VP test indicates that your unknown was able to do a mixed acid fer-mentation.
Answer:
False

Question:
14. Biosafety Level 1 (BSL-1)
Answer:
-not known to consistently cause diseases in healthy adults -ex. Lactobacillus casei, Bacillus subtilis,
Rhizobium Ieguminosarum

Question:
15. Biosafety Level 2 (BSL-2)
Answer:
-Agents associated with human disease; treatments and/or vaccines are usually available -routes of
transmission include percutaneous injury, ingestion, and mu-cous membrane exposure -ex.
Staphylococcus aureus, Salmonella enterica, measles virus

Question:
16. Biosafety Level 3 (BSL-3)

, Answer:
-Indigenous or exotic agents with potential for aerosol transmission -Disease may have serious or
lethal consequences; treatments and/or vaccines maybe be available -ex. Yersinia pestis,
Mycobacterium tuberculosis, rabies virus

Question:
17. Biosafety Level 4 (BSL-4)
Answer:
-Dangerous/exotic agents that pose a high risk of life-threatening disease, aerosol-transmitted lab
infections, or related agents with unknown risk of transmission; treatment and vaccines are
unavailable -ex. Ebola virus, Lassa virus

Question:
18. ocular lens
Answer:
10x




Question:
19. arm
Answer:




Question:
20. revolving nosepiece
Answer: