Exam I – Microbiology – Flashcards
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Prokaryote shapes |
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Bacillus (Rod) Coccus (Spherical) Spirillum (Twisted or curved rod) |
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Strepto- |
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Chain of bacteria |
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Staph- |
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Cluster of bacteria |
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Pleomorphic |
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Bacteria that are variable in shape |
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Surface-to Volume Ratios/Growth Rates |
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Small cells have adavantage relative to cell volume. They need less nutrients to successfully provide for the whole cell |
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Prokaryotic cytoplasm |
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Contains Nucleoid, ribosomes, inclusion bodies, and spores Composed of water and dissolved solutes Site of cell functions |
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Bacterial Cytoplasmic Membrane |
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Polar, hydrophilic head Nonpolar, hydrophobic tail Amphipathic phospholipid bilayer |
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Archael Cytoplasmic Membrane |
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Ether linkages (instead of ester) in phospholipids Lipids lack fatty acids Major lipids are diethers and tetraethers Monolayer or Bilayer |
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Simple transport |
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ATP or pmf for energy Moves molecules against the concentration gradient Involves carrier proteins Uptake of organic compounds |
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Group translocation |
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Chemical modifies molecule as it's brought into cell Sugar phosphotransferase system |
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Phosphotransferase system |
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Transports sugars while phosphorylating them using PEP as the phosphate donor |
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ABC transporters |
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ATP-Binding-Cassette In bacteria, archaea, and eukaryotes |
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Enzyme |
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Protein catalyst that accelerates cellular chemical reactions |
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Transcription |
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DNA produces RNA |
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Translation |
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RNA makes protein |
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Robert Hooke |
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Viewed cork slices under early microscope describing "cella" |
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Anton van Leeuwenhoek |
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Made microscope with 300x magnification First to view "animalcules" (Bacteria) |
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Francesco Redi |
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Meat in jar experiment disputing spontaneous generation |
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Louis Pasteur |
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Germ Theory Rabies vaccination Protection from cholera Protection from anthrax Pasteurization |
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Robert Koch |
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Proved Germ Theory Koch's postulates Pure culture technique |
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Eukaryotic Microorganisms |
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Fungi, Protozoa, Algae, Slime molds |
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Prokaryotic Microorganisms |
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Bacteria and Archaea |
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Phototrophs |
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Use light as energy source |
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Chemolithotrophs |
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Inorganic Chemicals as Energy Source |
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Chemoorganotrophs |
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Organic molecules as energy source |
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Domain Bacteria |
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All known pathogenic prokaryotes Proteobacteria is largest phylum |
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Proteobacteria |
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All gram negative |
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Archaea Phylums |
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Euryarchaeota Crenarchaeota |
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Euryarchaeota |
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Methanogens: degrade organic matter anaerobicall producing methane Extreme Halophiles: require high salt concentrations Thermoacidophiles: High temperatures and low pH |
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Crenarchaeota |
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Hyperthermophiles Live in marine, freshwater, or soil |
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Uniporter |
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Simple transport involving the absorption of individual molecules one at a time |
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Antiporter |
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Simple transport involving the absorption and removal of individual molecules at the same time |
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Symporter |
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Simple transport involving the absorption of multiple molecules at the same time |
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Protein Export |
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Translocation machinery moving proteins through and inserting into prokaryotic membranes |
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Gram-positive cell wall |
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One layer of membrane and one layer of peptidoglycan Contains large amounts of teichoic acids |
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Gram-negative cell wall |
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Double layer membrane with peptidoglycan in the perplasmic space between membranes |
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Periplasm |
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Gel-like space that lies between membranes in Gram-negative bacteria Contains high concentration of proteins |
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Archaea Cell Walls |
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No peptidoglycan, Pseudomurein instead No outer membrane Specialize for biological habitat |
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Capsule |
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Usually composed of polysaccharides and protein Well organized Not easily removed from the cell |
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Slime Layer |
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Diffusion Unorganized Easily Removed |
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Functions of Capsules/Slime Layers |
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Protection from host defenses (phagocytosis) Protection from environment Attachment to surfaces |
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Fimbriae |
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Shorter appendages Mediate attachment to surfaces |
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Pili |
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Some required from twitching/gliding motility Longer than fimbriae Less numerous than fimbriae Adheres pathogens to specific tissues Required for conjugation |
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Cell Inclusion Bodies |
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Granules of organic or inorganic material stockpiled for future use Some membrane bound Aquatic bacteria use gas vesicles to float Magnetostomes contain magnetite or greigite allowing response to magnetic fields |
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Endospores |
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Usually formed by Gram-positive bacteria Dormant and highly resistant to environmental conditions |
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Reasons for Endospore Resistance |
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Spore coat DNA repair enzymes present Dehydrate core Small acid-soluble, DNA-binding proteins |
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Sporogensis (Sporulation, Endospore Formation) |
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Starts when growth ceases due to lack of nutrients Complex, multistage process |
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Dormant spore to Active Vegetative Cell Process |
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Activation Germination Outgrowth |
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Flagella |
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Long appendages for motility Contain helical filament, hook, and basal body Rotation propels cell |
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Polar flagella distribution |
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Flagellum at end of cell |
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Monotrichous Flagella Distribution |
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One flagellum |
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Amphitrichous Flagella Distribution |
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One flagellum at each end |
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Lophotrichous Flagella Distribution |
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Cluster of flagella at one or both ends |
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Preitrichous Flagella Distribution |
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Flagellum spread over entire cell surface |
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Flagellar Movement |
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Counterclockwise causes forward motion (run) Clockwise disrupts forward motion (tumble) Powered by PMF in bacteria Powered by ATP in archaea |
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Microbial Taxis |
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Directed movement in response to chemical or physical gradients |
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Chemotaxis |
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Movements toward or away from a chemical stimulus Concentrations of chemical stimuli detected by chemoreceptors In presence of chemical attractant, tumbling frequency is reduced |
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Phototaxis |
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Response to light |
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Aerotaxis |
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Response to oxygen |
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Osmotaxis |
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Response to ionic strength |
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Hydrotaxis |
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Response to water |
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Microbial Nutrient Requirements |
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In high amounts: C, O, H, N, S, P, K, Ca, Mg In trace amounts: Fe, Mn, Zn, Co, Mo, Ni, Cu |
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Growth Factors |
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Essential cell components that the cell cannot synthesize Must be supplied by environment for successful cellular life |
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Classes of Growth Factors |
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Amino acids Purines and pyrimidines Vitamins |
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Photolithoautotroph |
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Carbon Source: CO2 Energy Source: Light Electron Source: Inorganic donor |
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Photoorganoheterotroph |
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Carbon Source: Organic carbon Energy Source: Light Electron Source: Organic donor |
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Chemolithoautotroph |
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Carbon Source: CO2 Energy Source: Inorganic chemicals Electron Source: Inorganic donor |
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Chemoorganoheterotroph |
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Carbon Source: Organic carbon Energy Source: Same as carbon source Electron Source: Same as carbon source |
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Catabolism |
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Energy conserving reaction that generates electrons |
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Anabolism |
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Synthesis of complex organic molecules from simpler ones |
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Energy from redox reactions stored in |
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ATP Phsophenolpyruvate (PEP) Glucose 6-phosphate |
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Proton Motive Force (PMF) |
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Protonse released during electron transfer Result in electrochemical potential across the membrane |
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ATP Synthase (ATPase) |
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Converts PMF to ATP |
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Microbial Growth Cycle |
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Lag phase Exponential Phase Stationary Phase Death Phase |
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Possible Reasons for starting Stationary Phase |
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Nutrient limitation Limited O2 availability Toxic waste accumulation Critical population density reached |
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Death Phase |
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Apoptosis Cells are viable but not culturable (VBNC) |
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Microbial Growth Range (Coldest to Hottest) |
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Psychrophile Mesophile Thermophile Hyperthermophile |
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Thermophile Adaptations |
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Protein and enzyme structures more heat stable Solute production stabilizes proteins Membrane stabilized by multiple means |
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Acidophiles |
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Growth optimum between pH 0-5.5 |
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Neutrophiles |
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Optimum growth between pH 5.5-8 |
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Alkalophiles |
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Optimum growth between pH 8-11.5 |
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Water Activity (aw) |
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Amount of water available to organisms Reduced by interaction with solute molecules Reduced by adsorption to surfaces |
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Osmophiles |
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Organisms that live in environments high in sugar as solute |
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Xerophiles |
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Organisms able to grow in very dry environments |
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Halophiles |
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Optimum growth at ~3% |
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Extreme Halophiles |
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Require >15-30% |
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Obligate Aerobes |
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Dependent on atmospheric oxygen for growth Growth only seen in oxygen rich areas of environment |
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Obligate Anaerobes |
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Die in presence of oxygen Only present in anoxic areas of environment |
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Facultative Aerobes |
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Grow better in presence of oxygen, but do not require it Uneven growth can be observed with more in oxygen rich area |
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Microaerophiles |
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Require lower than normal level of oxygen Uneven growth observed with more growth in anoxic environment |
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Aerotolerant Aerobe |
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Ignore oxygen levels during growth Uniform growth throughout entire environment |