OpenStax Microbiology Test Bank Chapter 9: Microbial Growth

OpenStax Microbiology Test Bank Chapter 9: Microbial Growth * = Correct answer Multiple Choice 1. Bacteria most commonly reproduce using which of the following methods? A. binary fission* B. budding C. meiosis D. mitosis 2. Which structure 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. death/decline phase ⟶ lag phase ⟶ log phase ⟶ stationary phase B. lag phase ⟶ log phase ⟶ stationary phase ⟶ death/decline phase * C. log phase ⟶ lag phase ⟶ stationary phase ⟶ death/decline phase D. stationary phase ⟶ log phase ⟶ lag phase ⟶ death/decline phase 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* 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* 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 to 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