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54 Cards in this Set
- Front
- Back
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Light (Brightfield) microscope
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what most labs today use, uses visible light for illumination
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Darkfield microscope
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uses a darkfield condenser so objects apppear bright against a dark background.
to see thin bacteria that do not stain well |
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Phase contrast microscope
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used to observe LIVING organisms without staining. Light is refracted (bent at an angle) differently by living things so they can be differentiated from the background
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Fluorescence microscope
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uses ULTRAVIOLET (UV) LIGHT to illuminate the object but light does not pass through the objective. Some dyes and pigments are said to fluoresce (glow) Organisms that pick up fluorescent dye typically appear bright green, yellow or orange against a dark background
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Electron microscope
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uses an electron beam as its source of illumination and magnets instead of lenses to focus the beam. There are two types of electron scopes TEM and SEM
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Transmission Electron microscope
TEM |
Used for viewing internal structures of microbes or tissues
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Scanning Electron Microscope
SEM |
Used to look at the surfaces and 3D structure
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Simple stain
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sufficient to determine bacterial shape and morphological characteristics (clusters, chains, pairs) Ex. methylene blue
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Gram Stain
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Differentiates bacteria into Gram-positive and Gram-negative organisms.
It is the first and most important step taken in the ID of the bacteria |
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Acid-fast stain
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Special stain for Myobacteria (caustive agent of tuberculosis or TB) because that organism does not stain well because of its cell wall
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Aseptic technique
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methods for keeping the environment or object free from pathogenic microorganisms
10% bleach and water for countertops Waiving loop, touching hot loop to colonies or agitating broth can create aerosols |
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Ocular lens
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Eye piece
10x magnifying lens |
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Revolving nosepiece
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Holds the objective lenses
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Objective lenses
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Used to magnify objects placed on the stage
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Stage adjustment knobs
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used to move stage
right to left and front to back |
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Iris diaphragm control arm
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located on the condenser
Used to adjust the amount of light passing through the condenser |
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Collector lens with field diaphragm
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Beneath condenser
Controls the amount of light entering the condenser |
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Rheostat control knob
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front side of base
Controls the amount of light emitted form light source |
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Field diaghragm lever
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Attached to field diaghragm
Used to adjust the amount of light passing through the collector lens |
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On/Off switch
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Turns the light source on and off
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Base
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Contains the light source
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Condenser control knob
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Beneath and behind condenser
Used to adjust the height of the condenser |
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Gram +
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gram+ bacteria stain purple because of the thick layer of peptidoglycan in their cell wall. it retains the 1st dye crystal violet.
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Gram -
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gram- stains red(pink) because of its thick layer of lipids (lipopolysaccharide) in cell wall.
The crystal violet does not penetrate cell wall. it stains pink because of the safranin stain after the decolorizer- acetone/alcohol pokes holes in lipopolycaccharide layer. |
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Gram stain procedure
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1.Allow smear to dry
2. Fix slide by dipping it in alcohol and allowing to air dry 3. Apply Primary Stain (Crystal Violet and stain for 1 min All cells are purple 4.Remove primary stain by rinsing for 1 min 5. Flood stain with mordant (Gram Iodine) and retain on the slide for 1 min. sets in the Crystal violet into the peptidoglycan layer of gram+ bacteria All cells are still purple 6. Remove mordant w/ tap water 7. Decolorize (Gram Decolorizer or Acetone/Alcohol) until solvent running from the slide is colorless (3-60sec) Pokes holes in lipopolysaccharide layer of gram- bacteria CV drains out of Gram- cell walls Gram+ is purple Gram- is colorless 8. rinse w/ tap water 9. Flood stain with counterstain (Safranin) and stain for 30-60sec Gram+ is purple Gram- is red(pink) 10. rinse w/ tap water 11. Blot w/paper towel or allow to air dry 12. Examine smear under an oil immersion lens |
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Supportive media
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Supports growth of non-fastidious microbes
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Enriched media
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Provides extra nutrients for fastidious microbes, and allows non-fastidious microbes to grow
BAP, CHOC |
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Selective
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Allows the growth of one gram stain morphology while inhibiting the other
This is accomplished with chemicals (antibiotics) and dyes. PEA, MAC |
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Differential
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Differentiates based on a specific characteristic after the colony grows on that agar plate
BAP-Differentiates based on hemolysis Alpha, Beta, and Gamma MAC- differentiates based on lactose fermentation LF vs. NLF |
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BAP
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Blood Agar Plate
enriched w/blood used for most fastidious organisms and to differentiate types of hemolysis Alpha-Partial hemolysis (green zone) around colony Beta- Total hemolysis (clear zone) Gamma- Non-hemolytic RBCs are intact surrounding colony |
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TSA
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Tryptic Soy Agar
Basic supportive media for Non-fastidious organisms |
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PEA
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Phenylethylalcohol Agar
Inhibits growth of Gram-neg. bacilli Encourages growth of most gram-pos cocci |
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CHOC
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Chocolate Agar
made w/blood that has been heated to liberate the hemoglobin required by some very fastidious organisms to grow |
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MAC
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MacConkey's Agar
Inhibits the growth of gram-pos cocci Encourages growth of non-fastidious gram-neg bacilli Also differentiates between lactose and non-lactose fermenting organisms Hot-pink if it ferments Clear, grey or pale pink if it does not ferment lactose |
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Colonial morphology
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Color
Shape elevation size texture odor hemolysis |
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Gram Stain Morphology
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Gram Stain color
Shape How they arrange themselves |
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what kind of bacteria form endospores
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Gram+ Bacilli
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MIC
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Minimum Inhibitory Concentration
The lowest amount of drug that completely inhibits the orgs growth not kill |
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Susceptible
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Organism is sensative to drug
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Intermediate
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Organism may be sensative to drug with higher doses
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Resistant
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Organism is resistant to drug
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Zone of Inhibition
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Area around disk or antibiotic that organism did not grow measured in mm
Agar is inoclated with a standard amount of an organism |
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0.5 McFarland standard
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Standarized inoculant concentration of organism
So results of testing is valid |
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kirby bauer/ KB method
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Agar incoculated with a standard amount of an organism. filter paper disks of an antibiotic is droped onto the plate and area around disk that the organism does not grow measured in mm is the Zone of Inhibition
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How do you make a bright field microscope function as a phase contrast microscope
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Drop the condenser down and close the diagphgam so not as much light shines through
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Brownian movement
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not true motility
It is caused by the continous back and forth movement of molecules in fluid. |
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True motility
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organisms that have a flagella has true motility. The flagella will propel them in a progressive directional path
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Pure culture
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one species of microorganism
We need to work with one culture in order to identify the specific microorganism we work with pure cultures to find out which antibiotic would work best to kill the organism |
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E. coli
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Gram neg. bacilli
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staphylococcus aureus
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Gram pos. cocci
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Endospores
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Are only formed by Gram pos. Bacilli
They have no cell walls therfore will stain pink |
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Autoclave
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Mechanical indicators- The gauges that indicate proper temp., pressure and time
Chemical indicators-indicate that the have been exposed to a sterization process but does not necessarilymean sterilization has been achieved. Tape and paper strips Biological Indicators- Only way to know that items are sterile. The endospores of Bacillus stearothermophilus are used |
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Colonial morphology
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Color-white grey, tan, yellow, pink, orange, green, clear
Shape-round, fried egg, feelers, fringy Elevation-dome shaped, concave button, flat, heaped Size-small, med, large, tiny pinpoint Texture-smooth, rough, mucoid, shiny, dull, creamy, waxy, crinkled Odor-butterscotch, roses, grape, german choc shake, bleach, dead mouse hemolysis- Alpha-Partial destruction (green zone) Beta-Total destruction (clear zone) Gamma- No hemolysis |
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Gram Stain Morphology
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Gram stain color
Shape (Bacilli, Cocci) How they are arranged |
