Exam I – Microbiology – Flashcards
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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 |
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