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96 Cards in this Set
- Front
- Back
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How small are microbes?
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10^-7 - 10^-3 M
Only visible by microscope. |
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What are the 6 major groupings of microbes? What categories do they fit into?
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Prokaryotes: Bacteria and Archaea
Eukaryotes: Algae, Protists, and Fungi Viruses |
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What is an organism's total genetic content called?
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Genome
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What is the name for infectious proteins? What do they do?
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Prions: causes proteins to take a misshapen form
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When was the light microscope invented? Who and when described the first cells?
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1660s: microscope invented
1665: Robert Hooke describes fruiting structure of molds |
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Who was the first to describe microbes in detail? When?
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1676: Anton von Leeuwenhoek (looked at the substances upon his teeth!)
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What three scientists (and when) did experiments to disprove spontaneous generation?
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Late 1600s: Redi - maggots /flies experiment
1700s: Spallanzani boils broth (no air) 1861: Pasteur uses swan-neck flask |
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How much of the planet's biomass is made up by microbes?
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60% (5x10^31 microbial cells)
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Can most microbes grow on typical mediums?
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No - they are mainly unculturable!
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What is a Winogradsky column? What occurs inside of one?
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A clear bottle containing mud mixed with shredded news (organic carbon source) which ultimately zones into different layers of microbes when exposed to light for several weeks; layers go from oxygen-rich conditions to highly reduced conditions.
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Microbes can be used to cycle many elements; name the four common cycles.
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1) Nitrogen (fix N2 to NH4, nitrify NH4 to NO3)
2) Carbon (photosynthetic microbes fix it) 3) Sulfur 4) Phosphorus |
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What is the theory that many diseases are caused by microbes?
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Germ Theory of Disease (Pasteur)
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In Germ Theory, how can resistant individuals not only become resistant, but in essence, prevent the spread of the disease?
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Vaccines
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How did Edward Jenner develop the first vaccine for smallpox in 1798?
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He used pustules from cattle as an innoculum based on observations from Lady Montagu and Turkish physicians.
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Which scientist described the microbiology of lactic acid fermentation, coined the terms aerobic and anaerobic for alcohol production from yeast, made a vaccine for chicken cholera from attenuated strain, and came up with an emergency vaccine for rabies?
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Louis Pasteur
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How did Robert Koch validate the germ theory of disease in 1876?
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He studied anthrax and determined that a bacterium was the cause of the disease.
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Who discovered the cause of anthrax, tuberculosis, and cholera?
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Robert Koch
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What were the four criteria for Koch's postulates?
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1) Microbe always present in diseased; absent in healthy
2) Microbe grown in pure culture with no other microbes present 3) Introduce pure microbe into healthy individual; they become sick 4) Same microbe re-isolated from new sick individual |
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Why did Robert Hooke come up with the name "cell"?
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When he looked at a cork, the dead plant material in cork reminded him of a jail cell.
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Who devised methods for staining bacteria, photographing, and preparing permanent visual records on slides in 1881?
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Robert Koch
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What is the name of the dye system for identifying bacteria? Who developed it in 1891?
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Gram Stain - Hans Christian Gram
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What are the two mediums that microbes (those that can, that is) can grow on?
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Broth - liquid containing all the nutrients the microbe requires
Agar - solid media, useful for wide range of temperatures |
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What is an antiseptic?
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A chemical that kills microbes.
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What was the first antibiotic discovered? When? By whom?
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Penicillin, 1929-1941, Alexander Fleming
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What are three advantages to studying microbes?
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1) Small - large populations easy to work with
2) Quick Growth - short generation times; easy to study life-cycle 3) Easy Growth - model microbes have simple requirements |
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Which experiment discovered the act of transformation in bacteria? By whom?
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Frederick Griffith: smooth/rough bacteria killing mice.
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What did the experiment by Avery and others that repeated Griffith's experiment but with various parts of the cell eliminated (protease, RNAse, DNAse...) prove?
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DNA is the hereditary material
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The first phylogenetic tree by Ernst Haeckel, 1866, had which three kingdoms?
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1) Plants
2) Protists 3) Animals |
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What were the original molecules, as seen in the Prebiotic Soup Model?
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H2O, NH3, CH4, H2
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Although Oxygen has been around since 4bya in small quantities, when did it really increase? What happened after this sudden increase in O2?
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2 bya; evolution of diverse life
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What does the banded iron indicate?
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Early life was attempting to use reduced iron and oxygen as an electron acceptor.
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What transformed the original Prebiotic Soup molecules into amino acids?
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Heat and Pressure and Energy (often in the form of lightning)
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What are the four criteria for a molecular phylogeny marker?
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1) Gene must be present in all organisms being compared
2) No gene transfer 3) Must have some sequence conservation 4) Large enough to have historical info |
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What is one of the best phylogenetic markers? Why?
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Ribosomal RNA; required for translation of mRNA into protein and is therefore present in all bacterial, archaeal, and eukaryotic cells.
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What two criteria must be met for changes in a sequence to constitute a molecular clock?
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Neutral and Random; number of differences between homologous macromolecules in two organisms should be a measure of time since they share a common ancestor.
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What occurs during vertical gene transfer?
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Passage of genes from parents to offspring or transfer of genes by replication or division.
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What occurs during horizontal gene transfer?
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Passage of genes among microbial lineages; confounds phylogeny deduced from sequences.
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What is the idea of the progenote?
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There was a common ancestor "community" of primitive cells as opposed to a single common ancestor. Genes would have been shareable amongst these microbes.
==> UNIVERSAL ANCESTOR |
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What are the two types of microbial cooperation?
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Symbiosis
Syntrophy |
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What is defined as the living together of two kinds of organisms?
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Symbiosis
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What is this circumstance: when one organism utilizes the by products from another organism?
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Syntrophy
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What is defined as analyzing ALL possible organisms/functions in a given environment based on DNA sequence; culture independent.
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Metagenomics
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What is mycorrhizae?
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A symbiosis between plant roots and fungi; plant provide nutrients, fungi fixes nitrogen for plants.
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What is the eukaryotic clade that contains fungi, multicellular animals, and some protist-like organisms?
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Opisthokonta
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Rhizopus is what kind of mold?
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Bread; multicellular structures with spores.
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What is a lichen a symbiosis between?
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Fungi with green algae or cyanobacteria ("blue-green algae")
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What are volvox? Porphyra?
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Green algae; red algae.
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What are red algae (porphyra) used for?
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Wrap sushi; wrap around seaweed
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What type of eukaryote is yeast?
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Unicellular fungi
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What do methanogens do?
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Carry out methanogenesis: use of hydrogen to reduce CO2 and other single carbon compounds to methane, yielding energy.
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Which type of archaea are important for waste-water treatment and nutrient cycling?
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Methanogens (Euryarchaeota)
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Which type of archaea live in intermediate temperatures but at extremely low pH's? What is interesting about them?
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Thermpolasmatales - only have a plasma membrane; no cell wall to protect them
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What distinguishes archaea from eukaryotes and bacteria?
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Ether-linked lipids: Archaea (forms lipid monolayer)
Ester-linked lipids: Bacteria/Eukarya |
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Why is the ether-linked lipids so important for archaea?
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They are much more stable in low pH's which is important since archaea live in extreme conditions.
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How did some bacteria (deep-branching thermophiles) acquire their ability to live in such extreme temperatures?
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Horizontal gene transfer
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Which type of bacteria became chloroplasts in modern-day plants?
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Cyanobacteria
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What is the function of cyanobacteria?
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Photosynthesis by day (produce oxygen)
Fix nitrogen by night |
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What are three key components of the cyanobacteria's cell structure?
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Carboxysome
Thylakoids Heterocysts |
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What is the function of a carboxysome in a cyanobacteria?
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Fixes CO2 using rubisco
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What is the function of the thylakoids in a cyanobacteria?
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Responsible for photosynthesis
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What is the function of the heterocysts in a cyanobacteria?
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Site of nitrogen fixation (N2 --> NH4+) using nitrogenase (enzyme that is oxygen sensitive)
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Which type of bacteria has two membranes with a small periplasm containing a very small layer of peptidoglycan?
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Gram-Negative Bacteria
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Which type of bacteria has one membrane bilayer with a large peptidoglycan layer and a S-layer protein "wall"?
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Gram-Positive Bacteria
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Which type of bacteria are well known for sporulation?
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Bacillus
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What is sporulation used for?
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Used to survive unfavorable environmental conditions by forming a durable, inert, heat-resistant spore (endospore) that can remain viable for thousands of years.
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Why is Bacillus thuriengensis used as an insecticide?
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It makes a protein that is so concentrated it forms a crystalline inclusion which is toxic to mosquitos.
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What is Bacillus antracis known for?
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First microbe grown in pure culture; causes anthrax
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Why is Epulopiscium fishelsoni special?
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It is a very large bacteria (quarter mm long)! Visible by eye; grows in symbiosis with a fish.
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Which bacteria is commonly used to make antibiotics?
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Streptomyces
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Which bacteria is a dangerous pathogen due to its waxy-coat? Why is it more dangerous? What does it cause?
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Mycobacteriacae - the waxy layer is less sensitive to antibiotics; tuberculosis
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Rhizobia, an alpha proteobacteria, is a symbiotic bacteria that does what?
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Provides nitrogen fixation for legumes (via the roots)
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What kind of bacteria are proteobacteria?
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Gram-negative bacteria
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Which Beta Proteobacteria lives in soil, is a dangerous pathogen to those with cystic fibrosis, is a powerful, metabolic organism and carries out degradation pathways?
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Burkholderia
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What kind of bacteria is E. coli?
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Gamma Proteobacteria; gram-negative
Grows in the human intestine; some are beneficial, others are detrimental (0157:H7) |
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What is an opportunistic pathogen?
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Most people are not affected by it; only causes infection or disease in an immune compromised host organism; wounds are susceptible.
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Which Gamma proteobacteria is an opportunistic pathogen that grows in many environments and is harmful to those with cystic fibrosis?
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Pseudomonas
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Why do myxobacteria (delta proteobacteria), such as Myxococcus xanthus, form fruiting bodies?
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When it runs out of nutrients (starvation) the cells aggregate to form a fruiting body so that it may disperse spores that may get to better suited environments.
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Borrelia burgdorferi and Treponema pallidum are examples of which kind of Gram-Negative Bacteria? What do they cause?
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Spirochetes:
Borrelia burgdorferi - Lyme's disease Treponema pallidum - Syphilis |
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What are metagenomics used for?
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Sequencing an entire community of microbes' genome without culturing them.
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How do metagenomics work?
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Extract DNA, use PCR to clone the sequence molecular phylogeny marker directly from the environment, sequence.
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Where was the large community of uncultured species from that was sequenced via metagenomics?
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Sargasso Sea by Bermuda
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What is an accumulation of microbes on the teeth?
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Biofilm: dental plaque
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When does tooth decay occur?
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When the wrong bacteria occur in too strong of a concentration.
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Termites eat soil and "wood"... Who is really digesting the cellulose in the wood?
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Microbes in the hind-gut (primarily bacteria, some eukaryotes, minimal archaea).
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When the bacteria or protozoa digest the cellulose in wood for termites, what is released? What happens to this? What is this an example of?
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Hydrogen is a by-product which is removed by methanogens (critical because otherwise it would build up to a high quantity). Synthrophy.
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How are all cells alike? (5)
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Double-stranded DNA
RNA Polymerase rRNAs and elongation factors Proteins - common functional domains Cell structure - aqueous cell compartments have a membrane |
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How do Archaea and Bacteria resemble each other but not Eukaryotes? (6)
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Smaller in size
Circular chromosome Nucleoids (no nucleus) Multigene operons (not single genes) Denitrification, N2 fixation, lithotrophy, respiration, fermentation (vs. resp. and ferm.) No complex multicellularity |
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How are bacteria and eukaryotes alike, different than archaea? (6)
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No methanogenesis
Limited growth at high temps Many species: photosynthesis Red and Blue chlorophyll light absorption Ester-linked fatty acids (vs. ether-linked) Many pathogens (vs. none) |
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What are the two kinds of gram-positive bacteria? What two examples do we have for each of those categories? (What are these examples known for?)
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Firmicutes: Bacillus (sporulation) & Epulopiscium fishelsoni (large)
Actinobacteria: Streptomyces (antibiotics) & Mycobacteria (thick cell wall; tuberculosis - waxy) |
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Steptomyces forms which cellular structure? What do they make? What is an example of that?
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Mycelia (branched filaments)
Secondary metabolites --> Antibiotics |
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How are all cells alike? (5)
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Double-stranded DNA
RNA Polymerase rRNAs and elongation factors Proteins - common functional domains Cell structure - aqueous cell compartments have a membrane |
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How do Archaea and Bacteria resemble each other but not Eukaryotes? (6)
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Smaller in size
Circular chromosome Nucleoids (no nucleus) Multigene operons (not single genes) Denitrification, N2 fixation, lithotrophy, respiration, fermentation (vs. resp. and ferm.) No complex multicellularity |
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How are bacteria and eukaryotes alike, different than archaea? (6)
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No methanogenesis
Limited growth at high temps Many species: photosynthesis Red and Blue chlorophyll light absorption Ester-linked fatty acids (vs. ether-linked) Many pathogens (vs. none) |
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What are the two kinds of gram-positive bacteria? What two examples do we have for each of those categories? (What are these examples known for?)
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Firmicutes: Bacillus (sporulation) & Epulopiscium fishelsoni (large)
Actinobacteria: Streptomyces (antibiotics) & Mycobacteria (thick cell wall; tuberculosis - waxy) |
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Steptomyces forms which cellular structure? What do they make? What is an example of that?
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Mycelia (branched filaments)
Secondary metabolites --> Antibiotics |
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Which is the best-studied gram-positive organism; the model system for "firmicutes"?
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B. subtilis
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