Review for Practical II

1
Review for Practical II

• Dr. Furlong
• BIOL 2250L
• By Thien Nguyen

2
Matching Temperature Range

• Mesophile
• Hyperthermophile
• Psychotroph
• Thermophile
• Psychrophile

• 65 to 120 (oC)
• 10 to 45 (oC)
• -10 to 20 (oC)
• 5 to 30 (oC)
• 40 to 75 (oC)

3
Matching Temperature Range

• Mesophile (B)
• Hyperthermophile (A)
• Psychotroph (D)
• Thermophile (E)
• Psychrophile (C)

4
Matching Optimum Growth Temperature

• Thermophile
• Psychrophile
• Mesophile
• Hyperthermophile
• Psychrotrop

• 37 (oC)
• 10 (oC)
• 25 (oC)
• 90 to 100 (oC)
• 55 (oC)

5
Indicate the following organisms as
(non-halophile, facultative halophile, or extreme
halophile) and state the optimal salt
concentration for each organism

• E. coli
• S. aureus
• H. salinarium

6
Answer

• E. coli (non-halophile) 1 salt
• S. aureus (facultative halophile) 1
• H. salinarium (extreme halophile) 20

7
Question

• What is the difference between viable and total
  counting?

8
Answer

• Viable count is counting only living cellsTotal
  count is counting both living and dead cells

9
Question

• What is the advantage and disadvantage of direct
  counting?

10
Answer

• Advantage accurate count of cells per
  volumeDisadvantage have to spread on plate and
  incubate of night, and very time consuming to
  count

11
Question

• What is the advantage and disadvantage of
  indirect counting?

12
Answer

• Advantage fast resultDisadvantage not as
  accurate as the direct counting method

13
Question

• What is the indirect counting method that was
  discussed in lab?

14
Answer

• An indirect method of counting is through the use
  of spectrophotometer to determine the
  transmittance and calculate OD to estimate the
  number of cells

15
Question

• What is serial dilution?

16
Answer

• Serial dilution is the dilution factor for one
  specific tube (SDAT/TV)

17
Question

• What does mean when the culture have a high OD?

18
Answer

• High OD meaning a low transmittance, which
  means the cell density is high

19
Question

• Why is it important to plate each dilution 3
  times?

20
Answer

• Each dilution is plated 3 times for accuracy

21
Which of the following plate is best for direct
counting method?
A
B
C
over 30 colonies
Under 30 colonies
30 300 colonies
22
Answer

• Plate A does not have enough CFU and does not
  provide an accurate representation of the
  concentration of cells per volume
• Plate C have too many cell and cant be count
• Plate B is the best plate to use because it is
  countable and provide a better representation of
  the concentration of cells per volume

23
Question

• What is it important to agitate the tubes before
  inserting it into the spectrophotometer?

24
Answer

• Agitating will resuspend the cell to have an
  equal concentration in the overall tube

25
Question

• What organism produces prodigiosin and under what
  condition does it produce this chemical?

26
Answer

• S. marcesens produces prodigiosin and it produce
  it only at optimal condition
• Temperature (25 oC)
• Salt (1)

27
Citrate Test
If an organism was inoculated into this tube and
it was able consume citrate as carbon source and
ammonia as nitrogen source. What would be the
result of this test be?
A
B
28
Answer
A
B
Tube A would indicate a positive result of the
organism ability to consume citrate and ammonia
29
Question

• What is the media and reagents require for the
  citrate test?

30
Answer

• Simmons Citrate Agar contains sodium citrate
  (carbon source), ammonium ion (nitrogen source),
  pH indicatorbromthymol blue.

31
Which one of these tube is a negative result of
the indole test?
B
C
A
32
Answer

• Tube B

A
B
C
33
Question

• What is the required reagent for the Indole test?

34
Answer

• Kovacs Reagent

35
Question

• What is the purpose of methyl red in the MR test?

36
Question

• Methyl Red is an indicator for the presence of
  acid

37
Question

• What does the Voges Proskauer (VP) test for?

38
Answer

• VP test for the production of acetoin from
  glucose fermentation

39
Question

• An organism was inoculated into H2S Production
  in SIM test. The result of the test is shown
  below. Is this a positive or negative result?

40
Answer

• The result is positive because the black
  precipitate is present

41
Question

• This is the result from a Urea Hydrolysis test.
  Explain the result.

42
Answer

• The pink tube indicate that the organism can
  hydrolyze urea to produce ammonia.
• The orange tube indicate a negative result, no
  ammonia was produce

43
Question

• Two different organisms was inoculated into
  Glucose Fermentation Gas production test. The
  result are below. Explain the result.

44
Answer

• Tube 2B Organism was able to ferment glucose to
  produce acid, but no gas production
• Tube 3A Organism was able to ferment glucose to
  produce acid and gas production

45
Question

• An organism was inoculated into M-Staph test.
  There is growth after a period of incubation.
  Can this organism tolerate salt?

46
Answer
Yes, it can tolerate salt because it was able to
grow
47
Question

• What are advantage and disadvantage of using the
  traditional biochemical methods to identify a
  pathogen?

48
Answer

• Advantageinexpensive and easy
• Disadvantagetakes a few days to get the results

49
Question

• Which antibiotic (A or B) is the organism more
  sensitive to?

A
B
50
Answer

• A (larger zone of inhibition)

51
Question

• An organism was inoculated into this glucose
  broth and the test and incubated for 24 hours.
  After 24 hours VP A and VP B reagents were added.
  
• What was the result of the test on this organism?
  
• What property does this media usually test for?

52
Answer

• Negative
• Acetoin from glucose fermentation

53

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