Microbial Growth

http://facultyfiles.deanza.edu/gems/gilleskay/15MYOAntarcticMicrobeCommuni.doc

•         The requirements for growth

o        Physical requirements

•         Temperature

•         pH

•         Osmotic pressure

o        Chemical requirements

•         Carbon

•         Nitrogen, Sulfur, phosphorus

•         Trace elements

•         Oxygen

·         Obligate aerobes

·         Obligate anaerobes

·         Singlet oxygen

·         Superoxide free radicals

·         Peroxide anion

·         Hydroxyl radical

·         Aerotolerant anaerobes

•         Organic growth factors

•         Culture media

o        Chemically defined media

o        Complex media

o        Reducing

o        Selective and differential media

o        Enrichment culture

•         Obtaining pure cultures

•         The growth of bacterial cultures

o        Bacterial division

o        Generation time

o        Logarithmic representation of bacterial populations

o        Phases of growth

•         The lag phase

•         The log phase

•         The stationary phase

•        The death phase

1. Distinguish between chemically defined and complex media.
2. Provide a use for each of the four elements (carbon, nitrogen, sulfur, and phosphorus) needed in large amounts for microbial growth.
3. Explain how microbes are classified on the basis of oxygen requirements.
4. Identify ways in which aerobes avoid damage by toxic forms of oxygen.
5. Justify the use of each of the following: anaerobic techniques, living host cells, candle jars, selective and differential media, and enrichment medium.
6. What is the technical name for bacteria that require a higher-than-atmospheric-concentration of carbon dioxide for growth? 
7. Define colony.
8. Describe how pure cultures can be isolated by using the streak plate method.
9. Compare the effectiveness of moist heat (boiling, autoclaving, pasteurization) and dry heat.
10. Describe how filtration, low temperatures, high pressure, desiccation, and osmotic pressure suppress microbial growth.
11. How is a plastic filtration apparatus presterilized? (Assume the plastic cannot be heat sterilized)
12. What processes are performed exclusively by bacteria in nitrogen fixation?
13. Define bacterial growth, including binary fission.
14. Compare the phases of microbial growth and describe their relation to generation time.
15. Classify microbes into five groups on the basis of preferred temperature range.