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Chapter 7 BSC 3271 Learning Outcomes
- Define doubling (generation) time.
- Calculate population size and doubling time (generation time) given the appropriate information.
- Given a description of the ingredients required in a growth medium for an organism, determine whether the organism needs any growth factors and what in the medium is a growth factor; define growth factor.
- Recognize the phases of the closed system growth curve and describe the physiological condition of cells and population dynamics at each phase
- Given data on population size at various time points, generate a growth curve and determine doubling (generation) time from the resulting graph.
- Describe under what kinds of conditions endospores form and germinate as well as the purpose of endospores.
- Identify the two genera of bacteria which can form endospores.
- Describe the mechanisms by which environmental factors affect the growth rate of microbes, particularly temperature, salinity, and oxygen.
- Provide the terms that describe organisms that thrive under various environmental conditions presence/absence of oxygen, high/low temperature, high salt, high/low pH.
Control of Microbial Growth
- Define the suffixes -cidal and -static.
- Identify major targets of physical and chemical disinfection and sterilization and explain why disruption of each will cause cell death.
- Distinguish between disinfection and sterilization.
- Describe how exposure time, microbial load, presence of spores or other resistant forms, and type of antimicrobial process (microbistatic vs. microbicidal) influence the effectiveness of disinfection or sterilization techniques.
- Describe the difference in effectiveness between moist heat and dry heat in killing microbes.
- Describe the effects of cold and dessication on cells.
- Explain how the following kill cells: ionizing radiation, UV (non-ionizing) radiation, surfactants (specifically quaternary ammonium compounds), chlorine and iodine compounds (halogens), alcohol, hydrogen peroxide, and heavy metals.
- Identify which physical and chemical methods can (practically) be used to sterilize.
- Describe how filtration can be used for sterilization
- Analyze a situation to identify the most suitable disinfection/sterilization techniques.
Thumbnail: "Klebsiella pneumoniae on C.L.E.D. Agar - detail" by Nathan Reading is licensed under CC BY-NC-ND 2.0