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66 Cards in this Set
- Front
- Back
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Microbe ecology is the study of
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microbes with their environments (and interactions wit each other).
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There are ____ prokaryotes on earth.
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10^30
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Microbes are _____ active and can change _____.
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metabolically; the environement they live in.
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Microbes are responsible for.....in the atmosphere.
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high levels of O2, low levels of CO2, N2 and methane
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Most microbes from environment cannot be _____.
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cultivated (<<1%).
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Enrichment cultures are used for...
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finding and using conditions that select for the microbes of interest
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What can happen when you change the conditions that a microbe grows in (usually a caution in enrichment cultures)?
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You can end of changing the phenotype.
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What is another caution in enrichment cultures that can occur?
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You can get no growth because some microbes only grow in communities.
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What does FISH stand for?
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Fluorescence in situ hybridization.
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What is FISH used for?
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To determine what is in the sample; it uses hybridization of the DNA and RNA (especially RNA because there are lots of copies of it) to selected Nucleic Acid probes (which are then fluorescently tagged).
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In FISH, the cells are _____ and you can order NA probes that ____.
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fixed to the slide, so they are dead; can pick up particular sequences that help identify what species are there (these NA probes are made with nucleotides that have fluorescent dyes attached).
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How is immunofluorescence like FISH, but different?
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it identifies the microbes by fluorescent tags, but it does it by antibodies instead.
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What does FACS stand for?
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fluorescence activated cell sorter
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What does FACS do?
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It uses tagged anitbodies to sort the cells, but these are used on LIVE cells; sorted by a fax machine that seperates them by whether the anitbodies fluoresce; it also collects live samples for you to try and grow.
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PCR allows you to identify...
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who is in a particular community, but the cells are dead so you can't grow them afterward.
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Micro-autoradiography uses....
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radioactive substrates to study metabolic pathways; uses film emulsion to detect if they are there.
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Explain the anoxic part of the carbon cycle.
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CO2 is in the atmosphere. It is turned to organic matter via carbon fixation. It then becomes CH4 through methanogenesis. It can also become CH4 from H2. The organic matter can also go through anaerobic respiration/fermentation to become CO2 again.
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Explain the oxic part of the carbon cycle.
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CO2 is in the atmosphere. It is turned to organic matter via carbon fixation. It then undergoes respiration (through the cycles aka pyruvate to acetyl CoA that releases some CO2. CO2 can also be made oxically from CH4 and CO.
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What are two greenhouse gases and the levels in our atmosphere?
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CO2 & CH4. There is 730 Gigatons of CO2 in the atmosphere, vs. the 1.1 million Gt of O2.
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What balances 100 Gt of CO2 each year?
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Photosynthesis removes it and Respiration & Decomposition forms it.
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How much CO2 is in Soil and Detritus, and how much is added each year?
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1600 Gt; +1.4 Gt each year.
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What balances 93 Gt of CO2 each year?
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Biological & Chemical processes in the ocean puts 93 Gt of CO2 in, and the same processes release 90 Gt per year. 3 of the Gt that goes in is transferred into sedimentation.
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How much CO2 is in the Ocean, and how much is added each year?
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38,000 Gt; + 1.9 CO2 each year.
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How much CO2 is in Oil, Coal, and Gas?
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5,000-10,000 Gt.
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So what is the reasoning behing Global Warming?
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That we are releasing 5.4 Gt of fossil fuel CO2 into the atmosphere each year. So we are burning more than we are depositing each year.
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How much CO2 in the atmosphere, and how much of an increase every year?
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730 Gt; + 3.2 CO2 every year.
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CO2 is consumed and trapped by ____ & _____.
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autotrophs and CaCO3 shells (which is why environmentalists are worried about the delicate balance of the ocean).
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How does CH4 relate to the 730 Gt?
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It doesn't. Although it is 8-20 times more potent as a heat trapping agent than CO2, it is a lighter and transiet gas, so it dissipates quickly.
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Most carbon is stored in ___ and slowly released by ____.
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rock (>99.5%); weathering and some by volcanism.
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Large amounts of methane (___) are trapped in _____ created by....
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10^4 Gt; hydrates (methane trapped in ice); archaea living and producing methane at great depths in the ocean or in very cold aqueous environments.
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Many environmentalists fear that the liberations of large volumes of methane as ocean temperatures rise may cause.....
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even greater global warming.
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The amount of O2 in the atmosphere is approx. ___
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1.1 mil Gt (large resevoir not easily perturbed)
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The biologoical processes (respiration vs. non-cyclic photo-phosphorylation) are.....
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perfectly balanced as are non-biological porcesses.
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N2 Fixation
__ + ___ ----> ____ + ____ This can be done by.... Ammonia is then assimilated to.... |
N2 + 8H ---> NH3 + H2; Free-living, aerobic, anaerobic, and symbiotic organisms; other nitrogen based products
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What happens after N2 fixation and assilimation?
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Ammonification occurs. Takes Organic N (from ammonia) to make NH4+. This is also called dissimilation.
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What occurs after Ammonification?
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Nitrification (NH4+ --> NO3-) This happens in two steps. NH4+ to NO2- then NO2- to NO3-
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What occurs after Nitrification?
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Denitrification. NO3- to N2 (or atmospheric Nitrogen).
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What is anammox?
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It is a step that can bypass ammonification to make 2NH2. It can only occur in certain microbes.
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What can occur in the sulfur cycle?
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Almost anything! sulfide/sulfur oxidation, sulfate reduction, sulfur reduction, sulfur disporportionation;
Many different redox rxns occur; |
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In the sulfur cycle, H2S and SO2 are released by...
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volcanism and industrial processes. These offset greenhouse warming.
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In the phosphorus cycle there is no _____, no ______, and cycling of phosphates is basically.... Is there any microbes involved?
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gaseous component, no redox chemistry involved; between soluble and insoluble forms. Not really.
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What is symbiosis?
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the living together or close association of 2 dissimilar organisms.
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What is mutualism?
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When two organisms live together for mutual benefit (both symbionts benefit).
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What is commensalism?
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Where neither symbiont is harmed, but usually one benefits while the other is unaffected.
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What is parasitism?
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Host is harmed, but parasite benefits.
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What is predation?
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Predator kills and consumes prey
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What is a classical case of mutualism?
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Nitrogen fixing of Rhizobia
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What happens in the case of Nitrogen fixing Rhizobia?
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When bio-available nitrogen is too low, plants release flavanoids (act as chemoattractants) that attract bacteria to fix nitrogen. Bacteria then makes NOD factors that cause plant cell devision and root hair curling. Bacteria then invade the plant cells, divide, & eventually differentiate into bacteriods.
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Do rhizobia fix nitrogen in any other case?
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They don't when they are free living. Just when attracted via flavanoids.
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What are specific to the bacteriods that the bacteria differentiate into?
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they are non-growing and N2 fixing.
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What is an infection thread?
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An infection thread is what is created after the curling of the root hair.It is the invagination of the cytoplasmic membrane that spreads through the neighboring cells. The bacteria then moves through the thread. It forms the nodule.
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What do you have to get rid of the allow N2 fixing?
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O2
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What is made to get rid of the O2?
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Leghemoglobin. Plant makes the protien part and the bacteria makes the heme part. The heme binds to the O2 to get rid of it.
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Leghemoglobin is only made _____.
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within the nodules.
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Rhyzobia require _____ provided by host when they convert to ____. They are used to....
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nutrients; bacteriods; generate ATP and reducing power for nitrogen fixing.
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Give another example of mutualism.
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Termites & Trichonympha. The Tric is a protozoa that lives inside the termites. Most vertebrates do not produce cellulase and can't digest plant food. Termites eat the wood that is digested by the Tric. Tric gets a home & constant food source.
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What is the lichen relationship considered as?
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Textbook says parasitic. Teacher says mutualistic.
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Explain the lichen relationship.
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Relationship between a fungus-algae or fungus-cyanobacteria. Fungi protect the partner from drying out by secreting acids that dissolve inorganics from rock. The photoautotrophs provide food by CO2 fixation and some N2 fixation by cyanobacteria.
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Explain mutualism in ruminants.
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Ruminants digest cellulose by the microbes in their rumen. Non-ruminants digest it in their XL intestines (cecum). Rumen is very anaerobic (pH ~ 65.) Rumen contains 200 sp. of bacteria at 10^10/ml. Lower #'s of protozoa. Cellulose is broken down by bac/pro; rumen bac ferment sugars to vFAs, CO2, & H2. Methanogens convert CO2 + H2 to CH4.
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Cows can produce ____ of methane per day.
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200-400 liters
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Predation and examples.
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The species invades other microbes and consumes the microbe from the inside.
Bdellovibrio, vampirococcus, daptobacter |
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Typically humans harbor ___ microbes.
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10^14
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Most human bacteria are consdered to be _____, but 10-20% of them are ______.
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commensals; potential pathogens.
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The large number of ____ outcompete pathogens for _____.
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non-pathogens; nutrients and space
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Large intestines contains _____ numbers of microbes that are mostly ___.
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large #'s (10^13 are eliminated each day); anaerobes.
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Explain the major initiative that occured in 2008.
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to catalogue and sequence SSU rRNAs from the 400 species of microbes in the large intestine in order to begin to understand their role in health and disease.
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