Exam Review #2, CSS360, Fall 2011
Oct 10th lecture:
1. What is the great plate anomaly? Explain why there is an anomaly. What are some
culture-independent methods that can be used to circumvent this problem?
2. Explain the central dogma of molecular biology (yes, again).
3. What is PCR? Briefly explain how PCR works and why it is done.
4. What is the Chloroform fumigation technique and why is it used?
5. Why would quantitative reverse transcription PCR (RT-PCR) be used instead of
quantitative PCR? What advantage does it provide?
6. Your goal is to both identify an organism and determine if it is able to metabolize
acetate. What method is most appropriate?
7. What is the difference between metagenomics and metatranscriptomics?
8. What general difference in diversity would you expect between plating a soil
sample solution on media and sequencing the 16S rRNA gene of the colonies VS.
using PCR to amplify all the 16S rRNA from the sample?
9. You are asked to assess the expression or abundance of >1000 genes in a soil
sample. What would be an appropriate method?
Oct 24th lecture:
1. Why do most soil bacteria live in biofilms?
2. What physical-chemical properties differ between the bulk soil and the
rhizosphere?
3. What is the difference between the rhizoplane and the rhizosphere?
4. Two plant rhizospheres are compared: One has a R/S ratio of 80 whilst the other
has a ratio of 40. Which rhizosphere would be expected to support more gramnegative bacteria?
5. Why are gram – bacteria generally selected over gram + in the rhizosphere?
6. What differences would you expect in the fungal and bacterial rhizosphere
communities between plants growing in fertile vs. infertile soils? What plant
characteristics affect these populations?
7. Describe how phenolic compounds may affect the microbial population AND
nitrogen availability in the soil?
8. Describe how increased plant diversity MAY affect the belowground microbial
community. How may this also affect nutrient supply to the plant?
9. Why are most plants resistant to bacterial pathogens?
10. What is the intermediate disturbance hypothesis? Why would diversity be
expected to increase at conditions that are not either extremely low nutrient or high
in nutrients?
11. Describe the priming effect and what impact this has on buried carbon deep in
the soil profile.
12. What role does the microbial community have on the P cycle?
Oct 31st Lecture
1. What are the general properties of fungi?
2. Why are fungi more suited to exploring niches for nutrients than soil bacteria?
3. What are the three nutritional states for fungi?
4. What is the role of fungi fruiting bodies?
5. What is the fungal mycelium? How does this differ from fruiting bodies?
6. How do the chytrids differ from most other fungi?
7. What fungal phyla forms sporangia?
8. What role do fungal mycelia play in sexual reproduction?
9. What is the following structure and what phyla does it belong to?
10. What is the following structure and what phyla does it belong to?
11. What phyla does this fungi belong to?
12. What is the general difference between the basidiomycota and zygomycota
reproduction?
13. Which fungal phyla has no known sexual reproduction?
14. What group does the following fungi belong to?
15. What are some characteristics of slime molds?
16. What is the difference between ecto- and endomycorrhizae?
17. What benefits do the fungi and plant gain from an ectomycorrhizal association?
18. Which type of mycorrhizae are the most abundant association with the greatest
variety of plants?
19. What is the role of the vesicles in vesicular-arbuscular endomycorrhizae?
Readings:
1. What happens with the microbial cycling of P when the C:P ratio is below and
above 100?
2. What role do mycorrhizal fungi have in providing P to plants?
3. What influences can different plants have on the quantity and quality of organic
matter?
4. What roles can hemiparisitic plants have on the plant community which they
invade? How can this affect the belowground community?
5. What did the study that investigated the impact of polyphenol production by
poplar to alders show?
6. How can specific plant traits influence and determine soil biological properties?
Synthesis Questions (Reading and Slides and lab):
1. Why would you think that plant species (or plant functional group) plays a more
important part in influencing the belowground community than overall plant
species richness?
2. How may mycorrhizae influence the structure of plant communities?
3. How may N fixers facilitate plant colonization of a poor soil?
4. What is a form of symbiosis (or mutualism) between fungi and another organism?
5. What is a CFU? How can a dilution series of a soil solution be used to estimate the
total number of bacteria in a soil? Is this an accurate representation of the number
of bacteria? Support your answer.