Download Study Guide 4 - Bacterial Growth Chpt. 4

Independent Study Guide ‐ Prokaryotic Growth (Chapter 4) I.
Principles of prokaryotic growth (section 4.1; figure 4.1) a. Binary fission b. Population growth c. Exponential growth (table 4.1) d. Generation time ‐ time it takes for a population to double in number II.
Bacterial Growth in Laboratory Conditions (section 4.4); Closed system ‐ the growth curve (figure 4.6) a. Lag phase ‐ synthesis of cell components preparation of cell division b. Log phase ‐ cells divide at a constant rate c. Stationary phase ‐ conditions deteriorate; rate of division = rate of death d. Death phase ‐ cells die off at a constant rate III.
Bacterial Growth in Nature (section 4.2); Open system a. Dynamic conditions b. Biofilms ‐ polysaccharide‐encased communities of microorganisms c. Mixed microbial communities IV.
Environmental Factors that Influence Microbial Growth (section 4.5) (table 4.2; do not memorize exact parameters, but know general environments) a. Temperature (figure 4.9) i. Psychrophiles ii. Psychrotrophs iii. Mesophiles iv. Thermophiles v. Hyperthermophiles b. Oxygen availability (table 4.3) i. Obligate aerobe ii. Facultative anaerobe iii. Obligate anaerobe iv. Microaerophile v. Aerotolerant vi. Role of superoxide dismutase and catalase c. Other terms i. Halophile ii. Halotolerant iii. Acidophile iv. Alkalophile v. Extremophile V.
Nutritional Factors that Influence Microbial Growth (section 4.6) a. To live/reproduce, all living things need: i. an energy source ii. a source of carbon and other required elements b. Energy sources i. Chemicals ("chemo") ii. Organic ("organo") iii. Inorganic ("litho") iv. Sunlight ("photo") c. Carbon sources i. CO2 ("auto") ii. Organics ("heterotroph") 1
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Required elements i. Nitrogen; organic nitrogen compounds, inorganic nitrogen compounds, N2 ii. Phosphorus is often a limiting nutrient in the environment iii. Iron is sequestered in the body, limiting microbial growth Growth factors – additional nutrients required by fastidious bacteria VI.
Cultivating Prokaryotes in the Laboratory (section 4.7); Characteristics of media used to cultivate bacteria (table 4.6) a. Complex vs. defined media i. Nutrient broth; complex (table 4.7) ii. Glucose‐salts; defined (table 4.7) b. Differential vs. selective vs. differential AND selective media i. Differential ‐ ingredient added that can be changed by bacteria in a recognizable way, e.g. blood agar (hemolysis) (figure 4.11) ii. Selective ‐ ingredient added that inhibits growth of many unwanted organisms, e.g. antibiotic‐
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Obtaining a Pure Culture (section 4.3); Pure culture – population of organisms descended from a single cell Study Questions When we talk about microbial growth, to what are we referring? If you start with a population of 100 cells of a species that has a generation time of 20 minutes, how many cells will you have two hours later? How many generations will have occurred? 3. What is a biofilm? Give an example. 4. What is a pure culture? 5. What is a solid versus a broth medium? 6. With respect to the growth curve, describe lag phase. 7. With respect to the growth curve, describe log phase. 8. With respect to the growth curve, describe stationary phase. 9. With respect to the growth curve, describe death phase. 10. During which phase of growth is the generation time measured? 2
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Describe an environment where a psychrophile would grow. Describe an environment where a psychrotroph would grow. Describe an environment where a mesophile would grow. Describe an environment where a thermophile would grow. Describe an environment where an obligate aerobe would grow. Describe an environment where an obligate anaerobe would grow. Describe an environment where a facultative anaerobe would grow. Describe an environment where a neutrophile would grow. Describe an environment where an acidophile would grow. Describe an environment where an alkalophile would grow. Describe an environment where a halophile would grow. What is a halotolerant bacterium? Metabolically, what is the difference between an aerotolerant anaerobe and a facultative anaerobe? What simple test can be used to distinguish an aerotolerant anaerobe from a facultative anaerobe? What is a photoautotroph? What is a photoheterotroph? What is a chemoorganoheterotroph? What is a chemolithoautotroph? Which nitrogen source can be used only by prokaryotes? Neisseria gonorrhoeae is fastidious. What does this mean? When would you use a defined medium rather than a complex medium? What characteristic of a bacterial growth medium makes it differential? Give an example of such a medium. What characteristic of a bacterial growth medium makes it selective? Give an example of such a medium. 3