BIOLOGY 206 - OpenStax Microbiology Test Bank Chapter 9: Microbial Growth, A+ Guide - St. Clair College.

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Chapter 9: Microbial Growth Multiple Choice 1. Bacteria most commonly reproduce using which of the following methods? A. binary fission B. budding C. meiosis D. mitosis 2. Which s... tructure separates new daughter cells in binary fission? A. the crescent B. the division septum C. the FtsZ D. the spindle apparatus 3. Which of the following is another term for generation time? A. doubling time B. growth rate C. mitotic index D. replication index 4. Which of the following best describes culture density? A. another term for a batch culture B. the number of cells per unit volume C. the reproducible pattern of growth D. the total number of cells 5. Which of the following is the correct order of phases of growth in the growth curve of a batch culture? A. B. C. D. 6. Which of the following is not a common way bacteria divide? A. binary fission B. budding C. fragmentation D. sporulation 7. Which of the following is the term for free-living bacteria? A. biofilms B. pathogenic C. planktonic D. sessile 8. Which of the following is not a reactive oxygen species? A. atmospheric oxygen B. peroxides C. singlet oxygen D. superoxide 9. Which of the following best describes FtsZ? A. a cytoskeletal protein in eukaryotic cells B. the protein that assembles the Z ring, which forms a divisome before division by binary fission C. the protein that forms within the central structure of the new cell wall and septum that separates the daughter cells during binary fission D. the protein that gives structure to spirochetes, contributing to their unusual shape and motility 10. Which microbial pathogen has an unusually long doubling time? A. Bacillus subtilis B. Escherichia coli C. Mycobacterium leprae D. Salmonella typhimurium 11. The initial cells added to a batch culture are called which of the following? A. the batch B. the culture C. the inoculum D. the lagging cells 12. Which best describes bacterial growth during the log phase of the growth curve? A. exponential B. linear C. S-shaped D. stationary 13. Which best defines the term “persisters?” A. cells that form endospores rapidly when environmental conditions become unfavorable, allowing them to survive in a dormant state without causing disease symptoms B. cells that persist in the log phase for much longer than other cells C. cells that rapidly colonize new environments by releasing virulence factors and moving through tissues, allowing them to contribute to severe systemic infections. D. cells with relatively slow metabolic rates that survive longer than others during the death phase and that can cause chronic infections ASM Standard: 14, 23 14. Which type of system is used to maintain bacteria in a relatively constant environment, allowing them to stay in the log phase of growth? A. bacteriostat B. chemostat C. maintenance state D. stable state 15. Which of the following is an indirect method of measuring numbers of bacterial cells? A. a Coulter counter B. a Petroff-Hausser chamber C. microscopic cell count D. turbidity measurements ASM Standard: 35, 36 16. Which of the following is not a common step in preparing a pour plate to make a count of microbial numbers? A. A serial dilution is performed. B. Bacteria are spread across the agar, using a sterile spreader. C. Bacteria are mixed with warm agar and poured onto a Petri plate, then swirled. D. The sample is allowed to grow, then colonies are counted. 17. Which of the following best describes why extracellular polymeric substances are important? A. They are chemicals produced as part of the immune response to microbial invasion. B. They are components of a biofilm secreted by the host cells as an immune response to wall off the pathogens. C. They are components of a biofilm secreted by the microbes present. D. They are secreted by free-living bacteria as virulence factors to allow them to penetrate the bloodstream. 18. Which of the following media is commonly used to determine the oxygen requirements of a bacterial species? A. chocolate agar medium B. Mueller-Hinton agar medium C. thioglycolate medium D. tryptic soy medium 19. Which of the following best describes how a microaerophile would grow in a thioglycolate tube culture? A. a short distance below the top of the medium, but not at the top B. at the bottom of the medium only, with no growth in the middle or top C. near and at the top of the medium, with no growth at the bottom D. throughout the medium 20. Which of the following is not an example of an enzyme used to detoxify reactive oxygen species? A. catalase B. permeases C. peroxidases D. superoxide dismutases 21. A candle jar is often used to grow which type of bacteria? A. capnophiles B. microaerophiles C. obligate aerobes D. obligate anaerobes 22. Which of the following is the most common category of bacteria? A. acidophiles B. alkaliphiles C. extreme alkaliphiles D. neutrophiles 23. Human pathogens are generally which type of microbe? A. mesophiles B. psychrophiles C. psychrotrophs D. thermophiles 24. Food spoilage is often caused by which type of microbe? A. mesophiles B. psychrophiles C. psychrotrophs D. thermophiles 25. Which type of microbes thrive in the Great Salt Lake? A. barophilic B. barotolerant C. extreme halophiles D. halotolerant 26. Which type of organism can survive at great depths in the ocean? A. acidophilic B. barophilic C. barotolerant D. halophilic 27. Which range of the electromagnetic spectrum is considered photosynthetically active radiation? A. from ultraviolet to near infrared B. from visible light to near infrared C. in near infrared only D. in visible light only 28. In batch culture, how does the log phase of the bacterial growth curve appear? A. exponential on a semi-log scale B. linear on a semi-log scale C. logarithmic on an arithmetic scale D. logarithmic on a semi-log scale 29. Which of the following best describes the enzymes of extreme alkaliphiles? A. They have many acidic amino acids. B. They have relatively high isoelectric points. C. They have relatively high numbers of negatively charged surface amino acids. D. They have the ability to pump protons out of cells. 30. Capnophiles are bacteria that grow best under which of the following conditions? A. relatively high CO2 and relatively low oxygen concentrations B. relatively high oxygen and relatively low CO2 concentrations C. relatively low CO2 and oxygen concentrations D. relatively low oxygen and CO2 concentrations 31. Which of the following best describes the cell membranes of microbes that thrive at low temperatures? A. They have only one layer. B. They have relatively even amounts of saturated and unsaturated fatty acids. C. They have relatively high amounts of saturated fatty acids. D. They have relatively high amounts of unsaturated fatty acids. 32. If you grow two species of bacteria on mannitol salt agar to determine which can ferment mannitol, and you know both species can grow on the medium, which type of medium is the agar? A. differential B. selective C. both a differential medium and a selective medium D. neither a differential medium nor a selective medium 33. Which of the following pigments are especially useful at great depths, where less light penetrates? A. bacteriorhodopsin and carotenoids B. carotenoids and chlorophylls C. fucoxanthin and carotenoids D. fucoxanthin and phycobilins 34. Which of the following microbes uses light energy to pump hydrogen and sodium? A. Bacteriodetes B. Campylobacter C. Chlamydomonas D. Halobacterium 35. Which of the following is true of using a Petroff-Hausser chamber to do a direct cell count? A. Identical squares, all the same size, are etched into the slide. B. If the sample was diluted, then the concentration must be corrected accordingly. C. It is not necessary to know the volume of the sample added to the slide. D. The chamber does not resemble a hemocytometer. 36. Which of the following would be the best choice for distinguishing living and dead bacteria in a cell count? A. using a Coulter counter or other electronic counting method B. using a streak plate, spread plate, or pour plate C. using gram staining or a similar method D. primary and secondary fluorescent stains 37. What is the goal number of CFUs on a spread plate if a serial dilution is done correctly? A. 1–10 per plate B. 30–300 per plate C. 400–900 per plate D. 1000 or more per plate True/False 38. The largest component of the dry weight of a biofilm is usually extracellular polymeric substances. 39. Generation time in prokaryotes refers to the amount of time required for the doubling of the population through a single round of binary fission. 40. Estimates of coliforms in water are often made using most probable number techniques. 41. Quorum sensing always occurs between members of the same species. 42. Halotolerant microbes cannot grow without high concentrations of salt. 43. Fungi can generally thrive in drier environments than can bacteria. 44. MacConkey agar can be used to select for the growth of gram-positive bacteria, making it especially useful to study Enterobacteriaceae. 45. Some halotolerant microbes are important causes of food poisoning. Matching 46. Match each type of organism with the best description of its oxygen requirements. A. aerotolerant anaerobes B. facultative anaerobe C. microaerophile D. obligate aerobe E. obligate anaerobe 47. Match each type of microbe with the best example. A. aerotolerant B. facultative anaerobe C. microaerophile D. obligate anaerobe 48. Match each type of microbe with the best description. A. hyperthermophile B. mesophile C. psychrophile D. psychrotroph 49. Match each type of medium with the best description. A. chemically defined medium B. complex medium C. differential medium D. enriched medium E. selective media ASM Standard: 11, 20, 22, 33, 34 50. Match each microbe with the best description. A. Bacillus firmus B. Ferroplasma C. Geobacillus D. Halomonas Fill in the Blank 51. The process of division by which cells split from a parent filament is called ________. 52. The generation time for a particular bacterial species in a particular batch culture is called the ________. 53. Turbidity is measured using a ________. 54. When a spread plate is used to estimate bacterial numbers, the numbers are reported as ________. 55. ________ organisms do not require high salt concentrations for growth but can grow in salty environments. 56. ________ is a measure of available moisture. 57. ________is when the cell membrane moves away from the cell wall due to osmosis occurring within the cytoplasm. 58. At low temperatures, membranes become ________ fluid unless they are able to modify their composition. 59. The pigment used by Halobacteria to absorb light is called ________. 60. The process of freeze-drying microbes so they can be stored until needed is called ________. 61. ________ is an important accessory pigment used by brown algae to aid photosynthesis at low light levels. ASM Standard: 11, 20, 22 Short Answer 62. Which group of bacteria commonly divides using fragmentation? 63. Where are barophilic organisms found? 64. What happens during plasmolysis and what causes it? 65. What is the difference between the optimum oxygen concentration and the maximum permissive oxygen concentration? 66. What is the following equation used for and what do the variables n, Nn, and N0 refer to? Nn = N02n 67. Why do researchers often work with bacteria in the log phase of bacterial growth in a batch culture, rather than in other phases? Sample Answer: Bacteria in the log stage are most commonly used because of their relatively consistent characteristics (i.e., growth and metabolism) and susceptibility to disinfectants and antibiotics. 68. What are the most important signaling molecules for quorum sensing in gram-negative bacteria? How does this compare with the signaling molecules used by gram-positive bacteria? 69. What is the standard way to grow obligate anaerobes in the laboratory? 70. Why is MacConkey agar considered both a selective and a differential medium? 71. Why might you need to enrich media? 72. Give an example of a halotolerant species that can cause food poisoning. 73. Mixed bacterial infections can occur that include both facultative anaerobes and obligate anaerobes. What happens when these species coexist? 74. Staphylococci thrive on human skin. What does this tell you about their environmental requirements? 75. Explain how you would do a serial dilution beginning with 1 mL of your bacterial culture. 76. Why are microbes in the stationary phase of growth less susceptible to antibiotics? 77. Which enzymes that detoxify reactive oxygen species are present or absent in obligate anaerobes and aerotolerant organisms? 78. Why is an enzyme from Thermus aquaticus especially useful for PCR? . Brief Essay Essay Question Rubric RATING Failing Below Average Competent Advanced Criteria for evaluation Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical mistakes and misspellings. Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is somewhat incoherent. Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings. Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings. 79. Using the standard equation to calculate number of cells at each generation, how many cells would be present after four generations in a population undergoing exponential growth that started with a population of two cells? How does this compare with the size after four generations of a similar population that started with eight cells? ASM Standard: 35 80. Explain what factors influence the length of the lag phase in a batch culture, and why. 81. Why is it helpful for some bacteria, such as Staphylococcus aureus, to produce virulence factors during the stationary phase of growth in a batch culture? 82. There has been considerable concern about finding good ways to treat infections involving biofilms, such as those that develop on medical devices. What characteristics of biofilms complicate the treatment of infections involving biofilms? 83. What are some ways in which the structures of thermophiles and hyperthermophiles differ in order to help them thrive at high temperatures? [Show More]

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