Test #2 Review Questions
Note: These questions are not intended to be all-inclusive, nor will they be on the
test word for word. Rather, they are intended to give you an idea as to what I think
is important in this unit.
Microbial Metabolism and Growth
Be able to describe the energy sources, carbon sources, electron sources and
systems used for energy acquisition (electron transport? Photosystems?) for
Organotrophs, Lithotrophs, Autotrophs, Phototrophs, etc.
Be able to tell how oxidation and reduction are related to energy generation via
electron transport chains and photosystems.
If given a variety of standard reduction potentials for electron donors and acceptors,
be able to determine which pair would, theoretically, generate the most energy.
What is respiration?
What are the important endproducts of glycolysis? The Citric Acid (Krebs) cycle?
Fermentation?
Differentiate between the EMP, ED and PPS pathways. Pay particular attention to
how they are related to one another, the major endproducts of each, and the
purpose of each.
Where does electron transport happen in eukaryotes? In prokaryotes? How does
electron transport generate energy for ATP synthesis?
What is ATP synthase, and how does it work?
Be able to discuss all of the various processes driven by the proton motive force.
Which of these can also be driven by the Sodium motive force?
Why do microbes ferment?
What are some endproducts of microbial fermentations? Be able to name several
food and non-food examples.
What are the endproducts of oxygenic photosynthesis?
Be able to discuss the similarities and differences between oxygenic and anoxygenic
photosynthesis and between photosystems I and II (for the latter, focus on Figure
14.34 in notes).
Be able to discuss various forms of chlorophylls found in bacteria, and how they
allow biofilms to exist with different layers of photosynthetic bacteria.
What is reverse electron transport, and why do bacteria do it?
What is the Calvin cycle, and what are its major end-products?
Be able to discuss the various stages of the microbial population growth curve.
The Origin and Diversity of Life
When did microbes first evolve, and what types of metabolism did they most likely
have?
Be able to discuss various scientific models for how the first biological molecules
were formed.
When did oxygenic photosynthesis evolve, and why was this so important?
How do we know that eukaryotes evolved from prokaryotic ancestors?
Various hypotheses exist regarding the origins of viruses – be able to discuss them.
What are the basic tenets of natural selection? Show how the development of
antibiotic resistance as a result of taking an incomplete does of antibiotics follows
these tenets.
Be able to discuss the conflict between natural selection and virulence – and discuss
the trade-off hypothesis, the short-sighted evolution hypothesis and the coincidental
evolution hypothesis in light of this conflict.
Discuss several examples of how microbes may actually influence the evolution of
their hosts.
What are trophic levels, and which levels do bacteria fill in ecosystems?
Is a bacterial colony a population, a community or an ecosystem? Explain.
What is a biofilm? How do biofilms help bacteria survive?
Be able to discuss soil structure and the types of microbes you would expect to see
in each horizon/layer
What roles do microbes play in the soil food web? Give examples.
Discuss the relationships that exist between microbes and macrobes (plants) in the
rhizoplane and the rhizosphere.
Compare and contrast Endomycorrhizae and Ectomycorrhizae
Microbially speaking, how do wetland soils differ from non-wetland soils?
Differentiate between oligotrophic and eutrophic lakes. Show the types of microbes
that you would expect to find in each, and their relative abundances. Be sure to
discuss the relative size of oxygenic and anoxygenic layers in each.
How do marine ecosystems differ from freshwater ecosystems? How are they
similar?
What are Dead Zones, and how does the toilet you flush (or the fertilizers you use)
in Selinsgrove impact them?
What are biogeochemical cycles?
Be able to discuss the roles of microbes in the carbon cycle, the sulfur cycle, the
nitrogen cycle and the phosphorus cycle. Pay particular attention to those stages
that are largely, or exclusively driven by bacterial processes.
Which biogeochemical cycles produce greenhouse gases, and what are the roles of
microbes in these processes?
Be able to discuss specific examples of microbial mutualism, commensalism,
competition and predation.
Describe in detail the symbiotic relationship between Rhizobium and a legume host.
How is it established, and what does each partner get out of the relationship?
Describe the symbiotic relationship between ruminants and their microbial
partners. How does feeding grain to cattle promote the growth of E. coli while
feeding grass and hay tends to promote the growth of other types of microbes? Why
do cattle often get more or less the same nutrients no matter what you feed them?
Be able to discuss each example of an extreme environment that we discussed in
class, and to describe how microbes adapt to each of those environments (Chagnes
to cell walls, cell membranes, nucleic acids, metabolism, etc.)
Microbial Communication
Be able to describe what quorum sensing is, and the general types of molecules used
as quorum sensing molecules (AHLs, etc.) You do not need to know, nor recognize
specific structures.
Be able to describe how quorum sensing results in the production of light in Vibrio
fischeri, and the expression of virulence factors in Candida, Staphylococci,
Xanthomonas and Vibrio cholerae.
Quorum sensing not only mediates conversations between members of the same
species, but can also mediate conversations between different species, genera and
even kingdoms. Be prepared to discuss 1-2 examples of each of these kinds of
conversations in some detail, and to describe the outcomes of the conversations for
both species.
Big Problems, Little Solutions
What types of toxins exist in our environment, and what do we mean when we say
that microbes can bioremediate them?
Differentiate between bioleaching, biosorption, biosparging, bioventing,
biostimulationphytoremediation, enzyme-catalyzed treatment, and natural
attenuation.
What types of factors influence the efficiency of bioremediation? Use the Gulf Oil
Spill as an example.
Where do toxin-eating microbes come from?
What are biofuels? Be able to discuss the pros and cons of the biofuels that we
discussed in class.