Test 3 Biol 687 Microbial Ecology Spring 1996

Name____________________________

1. Discuss mycorrhizal-plant interactions with respect to benefits that both partners receive, potential interactions with other soil microbes, and why understanding the relationship may be important in agriculture and species conservation. (7)

 

2. Discuss the mammalian gut as a habitat, use the human gut and a ruminant gut as contrasting examples. Include the possible benefits to both microbes and host. Discuss the various sub-habitats present in both hosts. Explain why early investigators only received a partial picture of the gut microbes that were present, and how modern techniques may increase our knowledge of gut microbial community composition. (13)

 

3. Discuss the natural occurrence of light-producing bacteria, including their interaction with carrion, and two groups of marine organisms that gain benefit from association with luminous bacteria. (6)

 

4. Present three strategies that could be used to clean up a groundwater spill of mixed toxic organic compounds. Discuss the benefits and drawbacks of each. (9)

 

5. Complete the table. (20)

 

 

Habitat

 

Stresses (molecular/ physiological

 

Microbial physiology adaptations to deal with the stress

 

Hotsprings

 

 

 

 

 

 

Extreme cold (ice algae)

 

 

 

 

 

 

Hypersalinity

 

 

 

 

 

 

Deep ocean

 

 

 

 

 

 

Desert soils

 

 

 

 

 

 

 

6. What are some of the possible microbial impacts when a natural wetland is acidified? (5)

 

7. Discuss the possible modes of gene transfer between bacterial species, several factors that may influence this transfer, and why the transfer may be important in microbial phylogeny and release of genetically altered microorganisms. (10)

 

8. Relate the problems and benefits of each of 4 general strategies of determining microbial activity. (8)

 

9. How may microbial methylation pathways be detrimental to humans? (2)

 

10. How may microbes be used in bioremediation of industrial emissions into the atmosphere? (3)

 

11. How may microbes be useful in mining? (2)

 

12. Give two methods of producing fuel (methane and ethanol) using microbes. (3)

 

13. Discuss the use of Bacillus thuringiensis as a bacterial pesticide. (3)

 

14. What are key factors controlling microbial growth and community composition on human skin? (4)

 

15. Explain some benefits and drawbacks of using oxygen microsensors for microbial research. (5)