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40 Cards in this Set
- Front
- Back
Identify the parts of the microscope
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Pictures in Text Book p. 48 or Lab Manual p. 125 |
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Identify the parts of the microscope-- What is the ocular lens? |
the eyepiece; the lens close to the eye; magnifies the image, usually 10-fold (10X) |
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Identify the parts of the microscope-- What is the objective lens? |
--the selection of lens options provides different magnifications |
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Identify the parts of the microscope-- What is the condenser lens? |
--It does not magnify, if focuses the light on the specimen |
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Identify the parts of the microscope-- Iris diaphragm lever |
controls the amount of light that enters the objective lens |
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Rheostat |
controls the brightness of the light |
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Calculate total magnification |
Magnification is the product of the objective lens (4x, 10x, 40x and 100x) multiplied by the ocular lens (10x) Total Magnification = ocular lens X objective lens Example: 10X ocular lens, 100X objective lens Total Magnification = 1000X (ocular lens X objective lens: 10 X 100) |
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Know the steps to proper aseptic technique
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Every single growth media you inoculate should be labeled with the following:
--you or your groups name --the name or initials of the microbe added (the inoculant) --the type of sterile media that is present in the culture --the date Flame base to tip red hot (decreases aerosols) |
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Outcomes if aseptic technique is not done properly
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1) organisms could be introduced from the outside environment and cause contamination 2) you could contaminate the environment |
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Morphology and Arrangements-- What is morphology? |
the shape of an organism |
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Morphology and Arrangements-- What is arrangement? |
the way bacteria stay attached to each other after cell division |
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Coccus |
spherical shaped organism |
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Bacillus |
--rod shaped organism --most common |
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Morphology-- Vibrio |
comma shaped or bent rods |
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Morphology-- Spirillum |
loose wave like shape |
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Morphology-- Spirochete |
spiral shaped (tight corkscrew) |
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Arrangements-- Diplo |
arranged in pairs |
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Arrangements-- Strepto |
long chains or strings |
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Arrangements-- Tetrad |
groups of four |
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Arrangements-- Staphylo |
clumps or clusters |
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Arrangements-- Spirillum |
rarely are seen as anything other than single cells |
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Purpose of staining
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You can tell morphology of your organism and arrangement and its size. It is fast, inexpensive, and simple. |
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Procedure for creating a smear
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1) Write on slide --type of bacteria --up on one side with bacteria --your initials 2) loop onto slide 3) air dry 10-15 minutes 4) heat fix (will kill or attach bacteria) 5) let cool about 5 minutes 6) let sit in stain for 1 minute 7) rinse for 1 minute 8) dry (sandwich it in and pat dry only) |
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Importance of heat fixing
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It kills bacteria, attaches them to the slide
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Outcomes of simple stain vs. gram stain |
Simple stain: will help determine morphology and arrangement of your organism and its size Gram stain: will determine gram-negative or gram-positive bacteria in addition to determining morphology, arrangement and size. Gram (-) cells will look red under the microscope, Gram (+) will look purple under the microscope |
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Proper procedure for creating a gram stain
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--Crystal Violet (primary stain): all cells +/- will stain purple --Iodine: acts as a mordant, which is a substance used to set dyes (stick together) --Ethanol (decolorization step): Gram (-) will decolorize due to the smaller amount of peptidoglycan. --Safranin (counterstain): both types of cells will pick up safranin which is red in color. Safranin will be masked by the crystal violet dye. |
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Possible outcomes if gram stain is not done properly |
--decolorize too long is most likely source of incorrect results --over decolorize removes CVI complex from both (+/-) --under decolorize gram (-) cells still retain CVI complex --too thick emulsion and you will obtain incorrect results --aging cells lose their ability to resist decolorization |
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Purpose of MSA (Mannitol Salt Agar) and EMB (Eosin Methylene Blue) plates
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They are selective differential media. They inhibit the growth of some organisms while encouraging or enhancing the growth of others
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Know the selective and differential components of the MSA (Mannitol Salt Agar) plate?
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--selective component: salt --differential component: mannitol |
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Know the selective and differential components of the EMB (Eosin Methylene Blue) plate? |
--selective component: the 2 dyes --differential component: lactose or sucrose |
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What organism do you expect to grow/ferment/etc. on the MSA (Mannitol Salt Agar) plate? |
--differentiates s. aureus from all other members of the genus |
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What organism do you expect to grow/ferment/etc. on the EMB (Eosin Methylene Blue) plate? |
gram negative organisms |
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Physical identification of the MSA (Mannitol Salt Agar) plate and the organism
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--other staphylococci will appear pink or red and the medium remains unchanged |
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Physical identification of the EMB (Eosin Methylene Blue) plate and the organism
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--moderate fermenters will appear pink --non fermenters will be the normal color of the bacterium |
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Purpose of the streak plate
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--all colonies will be on the surface --streaking decreases cell density --allows for formation of colonies |
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Define colony
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--mound of cells growing on an agar that started as a single cell --to produce pure culture the colony can't touch other colonies and we can't be sure it came from one single bacteria |
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Define pure culture |
a population of cells resulting from the growth of a single cell
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Define mixed culture |
a culture consisting of 2 or more species of bacteria |
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Be able to identify mixed cultures and colonies |
??? |
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Know the significance of getting a colony |
Can help identify a microorganism |