Ch 6 micro

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XQWCat
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176674
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Ch 6 micro
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2012-11-17 22:44:04
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Microbiology
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Ch 6 micro test 2
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  1. The addition of which of the following to a culture medium will neutralize acids?A) BuffersB) SugarsC) pHD) HeatE) Carbon
    A
  2. Salts and sugars work to preserve foods by creating aA) Depletion of nutrients.B) Hypotonic environment.C) Lower osmotic pressure.D) Hypertonic environment.E) Lower pH.
    D
  3. The term facultative anaerobe refers to an organism thatA) Doesn't use oxygen but tolerates it.B) Is killed by oxygen.C) Uses oxygen or grows without oxygen.D) Requires less oxygen than is present in air.E) Prefers to grow without oxygen.
    C
  4. Which of the following is an advantage of the standard plate count?A) Can readily count cells that form aggregatesB) Requires incubation timeC) Determines the number of viable cellsD) Chemical and physical requirements are determined by media and incubation.E) Cannot be used to count bacteria in food
    C
  5. Which of the following is an advantage of the direct microscopic count?A) Can readily count organisms that are motileB) Enumerates dead cellsC) Requires no incubation timeD) Sample volume is unknown.E) Requires a large number of cells
    C
  6. Which of the following is NOT used to determine metabolic activity?A) Acid production from fermentationB) CO2 produced from the Krebs cycleC) NO2- produced from the electron transport chainD) Decreased dissolved oxygenE) Turbidity
    E
  7. Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?A) 4B) 9C) 18D) 36E) 72
    D
  8. Most bacteria grow best at pH
    A) 1.B) 5.C) 7.D) 9.E) 14.
    C
  9. A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a(n)A) Selective medium.B) Differential medium.C) Enrichment culture.D) A and BE) B and C
    D
  10. A culture medium consisting of agar, human blood, and beef heart is aA) Chemically defined medium.B) Complex medium.C) Selective medium.D) Differential medium.E) Reducing medium.
    B
  11. Which of the following pairs is mismatched?A) Psychrotroph – growth at 0°C  B) Thermophile – growth at 37°C  C) Mesophile – growth at 25°C  D) Psychrophile – growth at 15°C  E) Hyperthermophiles – growth at 100°C
    B
  12. During which growth phase will gram-positive bacteria be most susceptible to penicillin?A) Lag phaseB) Log phaseC) Death phaseD) Stationary phaseE) The culture is equally susceptible during all phases.
    B
  13. Which of the following is the best definition of generation time?
    A) The length of time needed for lag phaseB) The length of time needed for a cell to divideC) The minimum rate of doublingD) The duration of log phaseE) The time needed for nuclear division
    B
  14. Which of the following is NOT a direct method to measure microbial growth?A) Direct microscopic countB) Standard plate countC) FiltrationD) Metabolic activityE) MPN
    D
  15. Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?A) PsychrophilesB) Facultative halophilesC) AnaerobesD) ThermophilesE) Hyperthermophiles
    B
  16. Which of the following is an organic growth factor?A) Glucose  B) NAD+  C) Peptone  D) NH4H2PO4  E) H2O
    B
  17. Which of the following is an example of a metabolic activity that could be used to measure microbial growth?A) Standard plate countB) Glucose consumptionC) Direct microscopic countD) TurbidityE) MPN
    B
  18. An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through?A) 64B) 32C) 6 D) 5E) 4
    D
  19. Three cells with generation times of 30 minutes are inoculated into a culture medium. How many cells are there after 5 hours?A) 3 × 210B) 1024C) 243D) 48E) 16
    A
  20. In one hospital, Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10% of 1300 patients who underwent gastrointestinal endoscopic procedures. After each use, endoscopes were washed with an automatic reprocessor that flushed detergent and glutaraldehyde through the endoscopes, followed by a tap water rinse. P. aeruginosa 10 was not isolated from the detergent, glutaraldehyde, or tap water. What was the source of the infections? A) Bacterial cell walls in the water B) A biofilm in the reprocessor C) Contaminated disinfectant  D) Fecal contamination of the bile ducts
    B
  21. Assume you inoculated 100 cells into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 24 hours, you should haveA) More cells in the 100 ml.B) More cells in the 200 ml.C) The same number of cells in both
    C
  22. The source of nutrients in nutrient agar isA) Agar.B) Nutrient.C) Peptone and beef extract.D) Peptone and NaCl.E) All of the above
    C
  23. Which enzyme catalyzes the reaction:  O2- + O2- + 2H+ → H2O2 + O2?
    A) CatalaseB) Oxidase C) PeroxidaseD) Superoxide dismutase
    D
  24. Which enzyme catalyzes the reaction:  2H2O2 → 2H2O + O2?A) CatalaseB) OxidaseC) PeroxidaseD) Superoxide dismutase
    A
  25. Which enzyme catalyzes the reaction:  H2O2 + 2H+ → 2H2O?
    A) CatalaseB) OxidaseC) PeroxidaseD) Superoxide dismutase
    C
  26. Patients with indwelling catheters are susceptible to infections becauseA) Injected solutions are contaminated.B) Their immune systems are weakened.C) Infections can be transmitted from other people.D) Biofilms develop on catheters.E) Bacteria cause infections.
    D
  27. Assume you inoculated 100 facultatively anaerobic cells into nutrient agar and incubated the plate aerobically.  You then inoculated 100 cells of the same species onto nutrient agar and incubated the second plate anaerobically.  After incubation for 24 hours, you should have:
    a) more colonies on the aerobic plate
    b) more colonies on the anaerobic plate
    c) the same number of colonies on both plates
    C
  28. the term trace elements refers to
    a) the elements CHONPS
    b) vitamins
    c) nitrogen, phosphorus, and sulfer
    d) small mineral requirements
    e) toxic substances
    D
  29. Which one of he following temperatures would most likely kill a mesophile?
    a) -50 degrees C
    b) 0 degrees C
    c) 9 degrees C
    d) 37 degrees C
    e) 60 degrees C
    E
  30. Which of the following is not a characteristic of biofilms?
    a) antibiotic resistance
    b) hydrogel
    c) iron deficiency
    d) quorum sensing
    C
  31. Which of the following types media would not be used to culture aerobes?
    a) selective media
    b) reducing media
    c) enrichment media
    d) differential media
    e) complex media
    B
  32. An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an:
    a) aerobe
    b) aerotolerant anaerobe
    c) obligate anaerobe
    B

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