Lab Exam 1 – Flashcards
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| Supplemented thioglycollate |
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| used to assess aerotolerance but has added nutrients for growing bacterial cultures |
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| Kirby Bauer Test |
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| tests antibiotic sensitivity -uses standardized conditions of 1/4 inch thick Mueller-Hinton agar plates; pH between 7.2-7.4; lawn made from .5 McFarland turbidity standard; antibiotic discs have a standard amount of antibiotic in them -procedure: Label plate; innoculate plate to create lawn; apply antibiotic discs without overlapping zones of inhibition; press discs firmly into agar so they stick; invert plates and incubate. |
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| broad spectrum antibiotic |
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| effective against both gram positive and gram negative cells -used when specific bacteria causing infection is unknown |
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| narrow spectrum antibiotic |
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| effective against either NOT BOTH gram positive and gram negative cells -used when cause of infection is known - prevents killing off good bacteria in the body |
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| S10 |
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| Streptomyocin -gram negative narrow |
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| C30 |
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| Chloramphenicol -broad spectrum |
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| CF30 |
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| Cephalothin -broad spectrum |
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| TE30 |
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| Tetracycline -broad spectrum |
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| P10 |
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| penicillin -not effective |
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| NB 30 |
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| Novobiocin -gram positive narrow |
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| S10 |
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| Streptomyocin -gram negative narrow |
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| E15 |
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| Erithromyocin -gram positive narrow |
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| VA30 |
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| Vancomyocin -gram positive narrow |
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| E. coli gram ... |
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| negative |
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| S. aureus gram ... |
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| positive |
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| Antiseptic |
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| used on living tissue -longer contact time (time it continues to work) -iodine |
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| Disinfectant |
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| -used on inanimate objects -decreases number of bacteria, but not sterilizing -bleach |
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| confluent growth |
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| continuous bacterial growth without discrete colonies |
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| lawn on agar plate |
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| covering the entire surface of a plate with bacteria to grow -start in middle and do one half, back and forth; then start in middle and do other half; rotate 90 degrees; start in middle and do one half; then start in middle and do other half |
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| gram negative bacteria are more resistant to antibiotics because |
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| of their outer membrane |
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| Gram positive cells are more or less susceptible to antibiotics than gram negative cells? |
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| Gram positive cells are more susceptible |
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| Zone of inhibition |
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| -area of no bacterial growth around an antibiotic disc -measured in mm |
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| resistance OR susceptibility to antibiotic shown through zone of inhibition |
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| must compare measurement to standardized chart |
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| aseptic technique |
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| -used to prevent contamination/keep cultures pure -procedure: use inner blue cone on bunsen burner; sterilize loop; remove cap of tube with little finger; flame tube; cool loop on tube; flame tube; close tube; innoculate culture with loop; sterilize loop |
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| streak plate technique |
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| -purpose: to isolate a single colony -procedure: streak loop across plate in 1/4 of plate; sterilize loop; rotate plate; cool loop on agar; drag through previous section 2-3 times and then streak another 1/4 of plate; sterilize loop; rotate plate; cool loop on agar; drag through previous section 2-3 times and then streak another 1/4 of plate; sterilize loop; rotate plate; cool loop on agar; drag through previous section 2-3 times and then streak remainder of plate; sterilize loop |
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| errors in streak plate technique |
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| -digging loop into agar -too many streaks through last quadrant before moving on to next quadrant -overlapping streak sections creating confluent growth |
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| BSL |
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| Bio Safety Level |
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| precautions used for BSL 1 and 2 |
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| -goggles -gloves -lab coats -close toed shoes -long pants -hair pulled back -disinfectant for tables -sterilization of tools -autoclave contaminated materials |
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| biohazard disposal |
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| -double bag anything that goes in biohazard bin -biohazard glass or sharps go in red biohazard sharps container -gloves inside out in biohazard bag |
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| Broth is used for: |
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| ?? |
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| slant is used for: |
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| -using less media than a plate (cost) ?? |
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| plate is used for: |
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| -identifying growth patterns (shape, margin) -isolating pure colonies |
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| aseptic |
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| pure (not sterile) |
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| sterile |
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| no living organisms |
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| Thioglycollate |
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| prepared using autoclave to remove all O2 -as it cools, the O2 reenters, creating an O2 gradient from aerobic to completely anaerobic in bottom of tube |
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| Obligate aerobe |
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| needs O2 to survive -only on top of tube |
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| Obligate anaerobe |
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| needs no O2 to survive -only on bottom of tube |
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| Facultative anaerobe |
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| prefers O2, but can adapt to grow without it -grows anywhere, better on top |
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| microaerophile |
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| loves a LITTLE O2 -grows in a band about 1/3 way down the tube |
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| Aerotolerant anaerobes |
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| prefers no O2, but can tolerate growth with O2 -grows anywhere, but better on bottom |
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| maximum temperature |
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| highest temperature for cells to be able to grow |
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| minimum temperature |
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| lowest temperature for cells to be able to grow |
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| optimum temperature |
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| best temperature for cells to be able to grow - highest growth rate |
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| cardinal temperatures |
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| range defined by the three temperatures in the range: -optimum -maximum -minimum |
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| temperature range |
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| the temps between the highest and lowest that an organism will tolerate to grow |
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| psychrophile cardinal temperatures |
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| Range: -5 to 15C Optimal: 10C icecap |
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| psychrotroph cardinal temperatures |
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| Range: -3 to 35C Optimal: 25C Santa Cruz |
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| mesophile cardinal temperatures |
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| Range: 15 to 45C Optimal: 40C rainforest; human pathogens |
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| thermophile cardinal temperatures |
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| Range: 40 to 80C Optimal: 70C hot spring |
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| extreme thermophile cardinal temperatures |
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| Range: 65 to 110C Optimal: 95C hot spring |
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| procedure for determining temperature category of microorganism |
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| -inoculate multiple specimens and grow at several different temperatures -compare growth on all plates to rule out temperature ranges where there was no growth -choose temperature category that includes all temperatures where there was some growth in medium |
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| hypotonic |
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| -fewer ions outside cell -low osmotic pressure -water moves into cell |
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| hypertonic |
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| -more ions outside cell -high osmotic pressure -water drawn out of cell, so plasma membrane shrinks away from cell wall (plasmolysis) |
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| isotonic |
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| -same amount of ions (osmotic pressure) inside and outside cell -fluid moves at same rate into and out of cell -0.85% osmotic pressure |
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| plasmolysis |
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| plasma membrane shrinks away from cell wall due to cell being in hypertonic solution |
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| halophile |
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| loves hypertonicity |
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| facultative halophile |
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| range: 0.85% to 15% -can grow with hypertonicity) |
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| obligate halophile |
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| range: must have over 3% |
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| extreme halophile |
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| range: must be over 15% up to 20% |
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| halotolerant |
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| can grow up to 5% but not well |
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| non-halophile |
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| grows most abundantly at 0.85% |
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| osmotic pressure order of organism tolerance |
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| non-halophile halotolerant facultative halophile obligate halophile extreme halophile |
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| order of organism tolerance (temperatiures) |
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| psychrophile psychrotroph mesophile thermophile extreme thermophile |
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| which osmotic pressure is closest to the average biological cell? |
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| 0.85% |
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| purpose of including water as a sample in disinfectant experiment |
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| control |
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| procedure for preparing bacterial smear slide from broth culture |
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| -label slide -use transfer technique to apply bacteria to slide (3-4 loops) -heat fix bacteria using hot plate and/or flaming slide |
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| procedure for preparing bacterial smear slide from plate/slant culture |
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| -label slide -add a drop of DI water to slide -use transfer technique to apply small amount of bacteria to slide -heat fix bacteria using hot plate and/or flaming slide |
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| what does heating a slide after applying bacteria do? |
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| -fixes the bacteria to the slide so they don't wash away -kills the bacteria |
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| simple stain |
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| single stain applied to cells which makes them visible under the microscope -allows determination of cell size, shape and arrangement |
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| procedure to prepare a simple stain |
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| -begin with prepared slide -drop stain onto smear and let sit for 1 minute -rinse with DI water -blot w bibulous paper |
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| gram staining tell us what? |
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| -differential stain gives you information about whether a cell is gram positive or gram negative (has thick peptidoglycan VS outer membrane) |
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| differential stain |
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| allows for detection of differences between organisms or structures within one organism |
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| stains adhere through |
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| ionic bonding |
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| gram staining steps |
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| -primary stain - crystal violet -mordant - iodine -decolorizer - alcohol -secondary stain (counterstain) - safranin |
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| general differential staining steps |
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| -primary stain -mordant -decolorizer -counterstain/secondary stain |
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| gram stain pink results |
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| gram negative (outer membrane) -E coli - short bacillus |
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| gram stain purple/black results |
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| gram positive (thick peptidoglycan) -S aureus - coccus -B subtilis - long bacillus |
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| Microscope parts |
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| -on/off switch -rheostat (dimmer switch) -light source (bulb) -condenser lens -condenser lens adjustment knob -iris diaphragm adjustment lever -specimen stage -specimen stage positioning knobs -coarse and fine focus knobs -objective lens -occular lenses -diopter adjuster in left ocular lens -interpupillary distance adjuster |
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| focal plane |
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| plane in space at which the lens is in focus (parfocal lenses have the same focal plane) |
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| how do you calculate magnification of an objective lens? |
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| multiply number on lens by 10 (for ocular lens magnification) |
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| parfocal objectives |
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| have the same focal plane; when they are exchanged they are very close to being in focus |
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| oil immersion improves resolution because |
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| it minimizes light refraction by removing air from the light path |
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| resolution |
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| sharpness of image |
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| magnification |
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| size of image |
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| Colony Morphology Shape (3) |
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-circular -irregular -punctiform (pin-point) |
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| Colony Morphology Margin (4) |
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-entire -undulate -lobate -filamentous |
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| entire |
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smooth edge colony morphology margin |
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| undulate |
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wavy edge colony morphology margin |
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| lobate |
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bumpy edge colony morphology margin |
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| filamentous |
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hairy edge colony morphology margin |
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| colony or slant morphology texture (3) |
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-moist -mucoid -dry |
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| colony or slant morphology optical properties (2 pair) |
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-opaque/translucent -dull/shiny |
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| slant morphology growth pattern (3) |
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-filiform -spreading -friable |
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| friable |
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| crusty |
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| filiform |
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-growth restricted to inoculation site -edge is clear and defined |
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| Broth cultures morphology (4) |
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-uniform fine turbidity -pellicle -sediment -flocculent |
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| Colony or slant Morphology Pigment |
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| Any |
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| Uniform fine turbidity |
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| uniform cloudiness |
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| Pellicle |
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| raft floating on broth |
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| sediment |
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| accumulation on bottom |
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| Plate morphology categories (5) |
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-shape -margin -texture -optical properties -pigment |
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| Slant morphology categories (4) |
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-texture -optical properties -pigment -growth |
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| procedure for loop transfer of culture (10 steps) |
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-sterilize loop -remove tube cap -flame tube mouth -cool loop on tube -dip loop -remove loop w/o flicking -flame tube mouth -close tube cap -innoculate plate, slant or broth -flame loop |
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| how to get single colonies on a streak plate (3 steps) |
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-4 quadrant -flame loop between each quadrant -drag cool loop through previous quadrant before moving into next |
