BIOLOGY 152; STUDY GUIDE: UNIT 5
Stuff in bold/red you may need to look up on your own (Tortora text)
Explain the following terms:
Plasmolysisenrichment mediageneration time
reducing mediacolony forming unit (CFU)
Answer the following questions:
- With regard to bacteria, what is meant by the term “growth”?
- Describe the process of binary fission in bacteria.
- Why is data for microbial growth generally plotted on a logarithmic scale rather than an arithmetic scale?
- Draw a graph representing a typical bacterial growth curve, and label and describe each of the four phases of the curve.
- How do temperature, pH, and osmotic pressure affect microbial growth?
- Compare and contrast psychrophiles, mesophiles, and thermophiles
- What is the difference between the minimum growth temperature, maximum growth temperature and optimum growth temperature?
- What are the four major elements that are required for microbial growth? Briefly describe why each of them is required.
- Describe the five categories of organisms in terms of oxygen requirements (i.e. obligate aerobe, obligate anaerobe, etc.)
- What criteria must culture media meet to make them appropriate for growing microorganisms?
- What material is used to solidify culture media and what is its source?
- What is the difference between a complex medium and a defined medium?
- What is the difference between selective media and differential media? Give an example of how each would be used?
- Given five different organisms with different oxygen requirements, describe the growth you would expect to see in a fluid thioglycolate broth culture of each.
- How does the catalase test work?
- Describe two ways of growing anaerobic cultures.
- Why are rickettsias, chlamydias, and viruses not grown on artificial media?
- What is a serial dilution? Why would one use a serial dilution?
- In a serial dilution where 1 ml of culture was plated from the 10-6 dilution, there were 253 colonies on the plate. What is the viable colony count of the organism?
- What is the difference between a pour plate and a spread plate for quantifying bacteria?
- Describe how each of the following would be used to measure bacterial growth:
- Plate counts
- Turbidity using a spectrophotometer
- Direct microscopic count