Serilize liquid media without harmingheat labile ingredints | Homework Helpers

1. This method can be used to serilize a liquid media without harmingheat labile ingredints:
a. autoclaving
b. pasteurization
c. freezing
d. cold filtration
e. aIDition of ethylene oxide to the media

2. Consider two parallel cultures. They are in all ways identicalexcept that one contains test substance X. You observe that abacterium you are studying grows equally well in both media.Therefore, test substance X is ___________.
A macronutrient
A micronutrient
An essential nutrient
A toxin
Not a nutrient

3. A microbe uses CO2 as its sole source of carbon and oxidizes H2 asits source of energy, to which nutritional group does this microbebelong?
Photoautotroph
Chemoorganotroph
Photoorganotroph
Chemoautotroph

4. A mutant bacterium does not produce a functional hydroxamate. Thisbacterium would have difficulty obtaining ___________.
Phosphate
Iron
Ammonia
Thiosulfate
Hydrogen sulfide

5. A medium containing methylene blue and incubated at 55º Cenriches for ______.
Mesophilic mycoplasma
Hyperthermophilic gram negatives
Gram positives
Thermophilic gram negatives
Thermophilic gram positives

6. Bacterium “A” has a growth rate constant of 4doubles/hour. Bacterium “B” has a generation time of0.25 hours/double. Which bacterium grows faster?
“A” grows faster than “B”
“B” grows faster than “A”
A” and “B” grow at the same rate
No conclusion can be made from this data

7. Assume you inoculated 100 cells into 100 ml of nutrient broth. Youthen inoculated 100 cells of the same species into 200 ml ofnutrient broth. After incubation for 12 hours, you should have
More cells in the 100 ml
More cells in the 200 ml
The same number of cells in both.

8. _________ halodurics use K+ as their osmolyte.
All
Some
No

9. A medium containing 3.2% NaCl and 0.025% phenethyl alcohol wouldenrich for _________.
Nonhalophiles
Gram-negative halodurics
Gram-negative halophiles
Gram-positive hyperhalophiles
Gram-positive halophiles

10. The value of the minimum inhibitory concentration dependsupon_________.
The microbe’s intrinsic sensitivity to the antimicrobial
The rate at which the antimicrobial diffuses through the agar
Both A and B
Neither A nor B

11. Which enzyme would be used to neutralize the activity of the[OH·] free radical?
Superoxide dismutase
Catalase
Peroxidase
Nitrogenase
None of the above

12. Which of the following can sterilize?
70% ethanol
10% sodium hypochorite solution
Ethylene oxide
Mecurochrome
All of the above

13. You are developing a new line of protease containing laundrydetergent. You plan on marketing the detergent to the NFL to removegrass and blood stains from their uniforms. You most likelyisolated the protease from which group of bacteria?
Acidophile
Neutrophile
Alkalophile
Strict anaerobes
Non-halophile

14. True or False: Fungi are better osmophiles than most bacteria.
True
False

15. The cell density of population of microbes expands six-thousandfold. Approximately how many times did the population double?
9
10
12
14
16

16. Thirty-six colonies grew on nutrient agar plate from 500?l ofundiluted sample in a standard plate count. How many cells / mlwere in the original sample?
17,000
900
18
36
72