Microbiology(Bio 210) Lab – Flashcards

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Arm
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connects base to body tube that contains lenses
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Compound microscope
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use two or more sets of lenses to magnify specimen
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Base
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light switch/on or off switch/voltage regulator
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ocular lens
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eyepieces
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Binocular
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two oculars
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Revolving nose piece
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10x magnification objective lens(low power)
40x magnification objective lens(high power)
100x magnification objective lens(oil immersion)
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Course adjustment knob
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large know on either side of arm that moves stage up or down rapidly to focus specimen
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Fine adjustment knob
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small knob in center of course adjustment knob that moves stage up or down slightly to adjust sharpness of specimen focus
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Stage
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platform that hold specimen
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Mechanical stage knob
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moves specimen around on stage
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Condenser
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directs and condenses rays from light source at base- can be moved up or down by knob on right side of arm below focus knobs
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Diaphragm
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opens and shuts condenser aperture to allow more or less light through condenser to specimen
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Blue filter
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blue glass in condenser(provides maximum resolution)
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Resolution
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the ability of a microscope to separate or distinguish between small objects that are close together
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To optimize resolution:
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-raise condenser
-open diaphragm
-use blue filter
-use immersion oil with 100x objective
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Total magnification
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The product of the magnifying power of the ocular lens x the magnifying power of the objective lens
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Parfocal
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the ability of a microscope to remain in focus when changing from one objective lens to another with little or no adjustment
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Immersion oil
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special type of mineral oil, this is used only with 100x objective lens to enhance focus and resoultion
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Index of refraction
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glass in the lenses
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Care of microscope
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1. lower stage before storing
2. turn microscope off
3. carry microscope with one hand on arm and other under the base
4.wrap power cord around base
5. use dust cover when done with microscope
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Ubiquity
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the state or capacity of being everywhere
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Characteristics of bacterium
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- unicellular
- Prokaryotic = bacteria lack a defined nucleus- no membranes-bound nucleus or organells
-cell is surrounded by a cell wall composed of peptidoglycan
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Common bacterial shapes
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-Bacilli(rods)
-Cocci(spherical)
-Spirals(helical or curved rods)
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Eukaryotic cells
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have membrane bound nuclei and organelles
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Non-photosynthetic
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do not have chloroplasts, and thus, cannot generate energy from light
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Mycetae
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the kingdom the fungi belong to
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Mycology
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the study of fungi
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Molds vs. Yeasts
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two morphological forms of fungi
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Molds
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filamentous growth that gives them a "fuzzy" or "cottony" appearance
-flament
-hyphae
-spores
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Hyphae
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filaments with terminal spores
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Septate
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hyphae-have crosswalls
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Non-septate
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hyphae- no crosswalls
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Mycelium
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a mass of hyphae that intertwines into a mat of growth
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Sporangiospores
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spores encased in a membranous sac called a sporangium
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Conidia
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spores are not encased in a sac- formed on a specialized hypha called a conidiophore
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Rhizopus(mold)
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has long non-septate hyphae with sporangiospores and root like hyphae called rhizoids. whiteish-gray w/ black dots
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Aspergillus (mold)
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has septate hyphae with conidia (black)
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Penicillium(mold)
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has septate hyphae with conidia (blueish/green)
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Yeast
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-form moist, smooth round colonies of growth on agar surface.
-cells are oval shape
-form budding cells that break away from parent cell
-unicellular
-pseudohyphae
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Saccharomyces(yeast)
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light bage
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Pseudohyphae
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chains of budding cells that are attached to parent cell
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Dimorphic/biphasic
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fungi that exists in both yeast and mold
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Sepsis
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unwanted growing
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Asepsis
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absent from contamanation
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disinfection
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decrease #'s of microorganisms
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Sterilization
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no life forms
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How to maintain an aseptic technique
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1.no contaminating microorganisms introduced into cultures that are being handled
2.the person manipulating the microbial cultures is not contaminated by the microorganisms being handled
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Procedure for aseptic technique:
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1. disinfect your area before and after each use
2.label all materials with your: name of culture,your name,section,exercise, and description of the medium
3.sterilize your loop across the bunsen burner until it is red hot
4.remove the cap and flame the tip of tube while still holding the cap in your hand
5.only lift the lid of the agar media enough for the loop to streak the surface
6. wash hands with soap
7. incubate your cultures
8. put materials away
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Pure culture
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a single cell divided and replicates exponentially, giving rise to a colony of cells that are identical progeny of the original parent cell
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Bacteria from isolated colonies may be differentiated by:
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1.color
2.shape
3. size,odor,texture
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Pure culture technique
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a method to dilute a large population of cells
1.streak plate
2.pour plate
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Streak plate method
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3 empty disks:
1. down 1/3 than streak 1
2. flame
3. 2x than don't touch
4.flame
5. 2x than don't touch
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Pour plate method
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1.remove a loopful of mixed culture and transfer it to tube 1
2.mix the tube and disperse evenly throughout the agar
3. remove a loopful of agar from tube 1 and transfer it to tube 2.mix tube 2
4. remove loopful of agar from tube 2 and transfer to tube 3.mix tube 3
5.pour all agar in tube 1 into dish 1.repeat this for tube 2 and 3
6. incubate
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Smear for broth culture
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transfer several loops of culture to the center of the target area/flaming the loop between each transfer
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Smear for agar slant or plate
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apply a small drop of water to the area where you will adding bacteria/mix the bacteria throughout the water droplet by using loop
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Good smear
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1. thin
2.durable
3.heat no disort the morphology
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Purpose of passing smear through bunsen burner:
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1. bacteria killed by heat
2. the cells with be "fixed"
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Simple staining
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a method of staining microorganisms with just a single strain
ex: methylene blue
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Basic dye
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bacteria is negative so stains that have positive polarity will bind readily to the cell by polar attraction
ex: methylene blue,crystal violet
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Acidic dye
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will be repelled by the cell/background is colored while the cells are colorless
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Pleomorphism
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they have varied or irregular shapes
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Metachromatic granules
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phosphate storing crystals, appear dark purple to pink
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Procedure for simple staining
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cell exposure for stain is 30 seconds-2 minutes. the stain is then rinsed off with distilled water,then blot dried and examined
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Gram staining procedure:
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1. prepare the slide by cleaning it 2.transfer cells to drops of water on target areas
3. air try and heat fix it
4. decolorization( using alcohol)
(use young cells)
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Gram positive
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-thick layer peptidoglycan
-retain primary stain- crystal violet
-purple
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Gram negative
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-thinner layer
-lose primary stain
-counterstrain- safranin
-pink or red
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What cell structure accounts for the major difference between gram+ and gram- cells?
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cell wall
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Differential stain
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telling two things apart based on criteria
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Standard Plate Count(SPC)
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Counts only the living cells based on the fact that each living cell will produce a colony on nutrient agar
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Countable plate
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# of colonies growing- between 30 and 300
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Obligate(strict) Aerobes
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require oxygen, grow at top of tube
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Obligate(strict) anaerobes
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cannot tolerate oxygen, grow lower 2/3 of tube
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Facultative
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can grow with and without oxygen, grow both places of the tube
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Microaerophilic
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these organisms need oxygen in amounts lower than atmospheric concentrations
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Aerotolerant
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organisms can grow in presence of oxygen but do not use oxygen in their metabolism
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Fluid thioglycollate medium(FTM)
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sodium thioglycollate will tie up oxygen to create an anaerobic environment in the lower portion of the tube.
-It contains resazurin, a dye that indicates areas that have been oxygenated
-the medium is pail pink or blue in presence of oxygen, near the surface of the medium
-incubated at 37 degrees C
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Brewers Anaerobic Jar
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Inoculate two nutrient agar plates with 3 bacterial cultures
- 1 plate incubated aerobically and 1 anaerobic jar
-incubate aerobic at 37 degrees C
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Psychorophiles
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Cold, grow at temperatures between -5 and 20 degrees C
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Mesophiles
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middle, grow between 20 and 40 degrees C
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Thermophiles
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hot, grow between 50 and 80 degrees C
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Hyperthemophiles
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grow at temps above 80 degrees C
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Prodigiosin
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a pigment produced by serratia marcescens only when pigment is affected by temp.
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Hypertonic Solutions
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cell shrinks, water goes from inside the cell to outside
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Hypotonic solution
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cell swells, water from outside goes into cell
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Isotonic Solution
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stays the same
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Halophile
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salt loving
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osmophile
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sugar loving
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Halotolerant
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are capable of growing in high concentrations of salt
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How UV light caused DNA damage?
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when UV light absorbs to DNA it causes pyrimidine dimers to form
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What allows some m/o to resist UV damage?
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-SOS system which removes the damaged dimer and inserts new pyrimidines. visible light is required
-Bacteria that form endospores are resistant to UV light
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What m/o possesses these cellular structures?
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Bacillus megaterium
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Antiseptic
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-kill or inhibit the growth of m/o on tissue
-"bacteriostatic" - mild
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Disinfectants
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-kills or inhibits m/o on surfaces
-"bacteriocidal" harsh/mostly kill
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How to measure zone of inhibition in antiseptics?
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measure from the edge of the disk to the edge of growth
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Zone of inhibition
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measured and compared to other zones of inhibition created by other reagents
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Kirby Bauer method
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media= Mueller Hinton Agar
measure= diameter of zone in mm
factors= pH,depth,porosity
interpret resistant, intermediate, sensitive by chart
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