Chapter 6 MULTIPLE CHOICE Choose the one alternative that best completes the statement or answers the question 1 Which enzyme catalyzes the reaction O2 O 2 2H H2O2 O 2 A superoxide dismutase C catalase B peroxidase D oxidase Answer A Table 6 2 The following data show growth of two bacteria on different media 2 The data in Table 6 2 indicate that S aureus is a n A aerobe B mesophile C halophile D facultative halophile E facultative anaerobe Answer D Figure 6 1 3 In Figure 6 1 which line best depicts a facultative anaerobe in the absence of O2 A a B b C c Answer B 4 Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt A psychrophiles B hyperthermophiles C anaerobes D facultative halophiles E thermophiles Answer D 1 5 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 4 B 9 C 18 D 36 E 72 Answer D 6 Which of the following is an advantage of the direct microscopic count A requires a large number of cells B can readily count organisms that are motile C sample volume is unknown D can easily distinguish live from dead cells E requires no incubation time Answer E 7 Which of the following pairs is mismatched A hyperthermophiles growth at 85 C B mesophile growth at 25 C C psychrotroph growth at 0 C D psychrophile growth at 15 C E thermophile growth at 37 C Answer E Figure 6 1 8 In Figure 6 1 which line shows the growth of an obligate aerobe incubated anaerobically A a B b C c Answer C 9 Three cells with generation times of 60 minutes are inoculated into a culture medium How many cells are there after 5 hours A 900 B 180 C 96 D 32 E 15 Answer C 10 Most bacteria reproduce by A fragmentation B binary fission C aerial hyphae D mitosis E budding Answer B 2 Figure 6 2 11 Figure 6 2 shows a typical bacterial growth curve with the x axis indicating the log of the number of bacteria and the y axis indicating time in culture In the figure which section or sections shows a growth phase where the number of cells dying equals the number of cells dividing A a B b C c D d E a and c Answer C 12 The addition of which of the following to a culture medium will neutralize acids A heat B carbon C buffers D pH E sugars Answer C 13 Which enzyme catalyzes the reaction H2O2 2H 2H2O A peroxidase B oxidase C superoxide dismutase D catalase Answer A 14 A culture medium on which only gram positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a n A enrichment culture B differential medium C selective medium D selective and differential medium E differential and enrichment culture Answer D 15 Salts and sugars work to preserve foods by creating a A lower pH B hypertonic environment C hypotonic environment D lower osmotic pressure E depletion of nutrients Answer B 3 16 A culture medium consisting of agar peptone and beef heart is a A reducing medium B chemically defined medium C differential medium D complex medium E selective medium Answer D 17 The source of nutrients in nutrient agar is A agar B nutrient C peptone and beef extract D peptone and NaCl E agar and NaCl Answer C 18 If cells are grown in media containing amino acids labeled with radioactive nitrogen 15N most of radioactivity will be found in the cells A DNA B proteins C phospholipids D DNA and proteins E DNA and phospholipids Answer D Table 6 1 Three different culture media are shown below Medium A Na2HPO4 Medium B Medium C KH2PO4 MgSO4 Tide detergent Glucose Na2HPO4 Peptone KH2PO4 NH4 2SO4 CaCl2 NaHCO 3 MgSO4 NH4 2SO4 KH2PO2 Na2HPO4 19 For the three types of media in Table 6 1 which medium or media is are chemically defined A A B B C C D A and B E A and C Answer A 20 Which enzyme catalyzes the reaction 2H2O2 2H2O O 2 A peroxidase B catalase C superoxide dismutase D oxidase Answer B 4 21 Which of the following is an example of a metabolic activity that could be used to measure microbial growth A turbidity B glucose consumption C direct microscopic count D standard plate count E MPN Answer B 22 The term aerotolerant anaerobe refers to an organism that A does not use oxygen but tolerates it B uses oxygen or grows without oxygen C requires less oxygen than is present in air D is killed by oxygen E requires more oxygen than is present in air Answer A Figure 6 1 23 In Figure 6 1 which line best depicts an obligate anaerobe in the presence of O2 A a B b C c Answer C 24 The biosafety level BSL for a clinical microbiology laboratory working with potentially airborne pathogens such as tuberculosis bacteria is A BSL 1 B BSL 2 C BSL 3 D BSL 4 Answer C 25 In one hospital Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10 percent 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 a biofilm in the reprocessor B fecal contamination of the bile ducts C contaminated disinfectant D bacterial cell walls in the water E None of the answers is correct Answer A 5 Figure 6 1 26 In Figure 6 1 which line best depicts a psychrotroph incubated at 0 C A a B b C c Answer B Figure 6 3 27 In Figure 6 3 which tube shows the expected growth pattern for a facultative anaerobe A a B b C c D d E e Answer B 28 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 have A more cells in the 200 ml B more cells in the 100 ml C the same number of cells in both D The answer cannot be determined based on the information provided Answer C 6 Figure 6 3 29 In Figure 6 3 which tube shows the expected growth pattern for a microaerophile A a B b C c D d Answer E 30 Which of the following is an organic growth factor A glucose B peptone C H2O D vitamin B1 E NH4H2PO4 Answer D 31 Patients with indwelling catheters are susceptible to infections because A their immune systems are weakened B bacteria cause infections C infections can be transmitted from other people D biofilms develop on catheters E injected solutions are contaminated …