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97 Cards in this Set
- Front
- Back
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What is the shape(morphology) of Bacillus cereus?
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Bacillus
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what is the arrangement of cells of Bacillus cereus?
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random
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which stain was used to stain Bacillus cereus?
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crystal violet
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what is the shape(morphology) of Escherichia coli?
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Bacillus
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what is the arrangement of cells of the Escherichia coli?
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random
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what color was Escherichia coli after staining?
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pink/red
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is Escherichia coli gram + or gram -?
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gram -
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what shape(morphology) is Staphylococcus aureus?
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Coccus
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what is the arrangment of cells of the Staphylococcus aureus?
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staphylo
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what color was Staphylococcus aureus after staining?
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purple
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is Staphylococcus gram + or gram -?
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gram +
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what is the shape(morphology) of Mycobacterium smegmatis?
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Bacillus
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what is the arrangement of cells of the Mycobacterium spegmatis?
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random
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what color was Mycobacterium spegmatis after staining?
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dark red
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is Mycobacterium spegmatis acid fast or non-acid fast?
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acid fast
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what shape(morphology) is Staphylococcus aureus?
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Coccus
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what is the arrangement of cells of Staphylococcus aureus?
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staphylo
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what color was Staphylococcus aureus after staining?
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teal
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is Staphylococcus aureus acid fast or non-acid fast?
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non-acid fast
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what is the correct term for the shape(morphology) of Bacillus?
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bacillus
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What is the correct term for the shape(morphology) of Staphylococcus?
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coccus
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what is the correct term for the shape(morphology) of Streptococcus?
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coccus
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what is the correct term for the arrangment of cells of Staphylococcus
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staphylo
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what is the correct term for the arrangement of cells of Streptococcus?
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strepto
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what is the difference between gram + and gram -?
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gram + has large amounts of peptidoglycan (PPG), lower lipid content, purple color is retained through decolorizer, and remains purple after applying counter stain bc they are bound with crystal violet.
gram - cells have a single layer of PPG, higher content of lipids, purple color is lost after decolorizer, and they are a pink/red color after using the counter stain. |
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what color is expected for gram + cells after using crystal violet?
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purple
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what color is expected for gram + cells after using iodine?
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purple
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what color is expected for gram + cells after using 95% ethanol(decolorizer)?
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purple
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what color is expected form gram + cells after using the counter stain safranin?
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purple
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what color is expected for gram - cells after using crystal violet?
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purple
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what color is expected after using iodine for gram - cells?
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purple
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what color is expected for gram - cells after using 95%ethanol (decolorizer)?
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no color
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what color is expected for gram - cells after using counter stain safranin?
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pink/red
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what color is expected for acid fast cells after using carbolfuschin?
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maroon/burgundy
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what color is expected for acid fast cells after using acid alcohol?
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maroon/burgundy
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what color is expected for acid fast cells after using brilliant green k?
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maroon/burgundy
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what color is expected for non-acid fast cells after using carbolfuchsin?
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maroon/burgundy
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what color is expected for non-acid fast cells after using acid alcohol?
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no color
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what color is expected for non-acid fast cells after using brilliant green k?
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teal/blueish color
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in differential staining procedures such as gram stain and acid fast stain what would be the consequence for gram - or non-acid fast cells if a counter stain was not used?
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you would not be able to see them because they would have no color
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if the mordant(iodine) was omitted what would be the probable gram stain reaction (color) for a gram + organism?
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the color would be pink/red. the cell walls would not be bound by crystal violet so they would be able to take up the color from the safranin.
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at the end of a gram stain, what color would a gram - organism appear if the decolorizer (95% ehtanol) was omitted during the gram staining procedure?
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purple. they would not appear pink/red because the safranin would not hold due to the cell walls being bound by crystal violet.
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what type of diseases would the acid fast stain be useful for?
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Tuberculosis. Acid fast stain is specific for genera Mycobacterium due to the presence of mycolic acids in the outer membrane of their cell walls which allow for unusual permeability properties.
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true or false: you perform a SIMPLE STAIN on an unknown organism using crystal violet as the stain. the specimen is purple when viewed under the microscope. this means that the organism is gram +
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if the procedure was done correctly then this is true because gram - cells cannot hold the purple color after using the decolorizer. if the decolorizer was not used then gram - cells would also appear purple.
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what is negative staining?
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a procedure which stains the background, leaving the organism untouched. the stain molds around the organism and outlines it. if portions of the organism are accessible to the stain they will be stained as well.
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you are given a sample of S. aureus. after performing a gram stian the final color result is pink. is this the gram stain result expected for S. aureus? explain.
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no. S. aureus is gram + so therefore it's final color result should be purple.
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what might cause S. aureus (gram +) to be pink at the end?
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too much decolorizer (95% ethanol)
not using mordant (iodine) |
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How do bacteria appear without staining?
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colorless. staining provides contrast for viewing
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what are the steps for performing a staining procedure?
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using sterile inoculating loop prepare a bacterial smear on slide
let air dry for 5-10 minutes heat fix slides perform staining procedures view under microscope |
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what is the first step in preparing a smear?
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wipe slide and label it
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what is a good example of a smear?
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thin, white layer. if samples are too thick they can stain unevenly and lead to false positive results. if it is too thin it can make it difficult to find the organism on the slide under the scope.
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what is a bacti-cenerator?
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instrument used to sterilize the inoculating loop.
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what is the purpose of the inoculating loop?
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to transfer small amounts of microorganisms from specimens or cultures to fresh culture media or microscope slides.
loop should be sterilized before, during, and after use. |
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what is the proper way to sterilize the inoculating loop?
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hold loop in dominant hand
insert loop into bacti-cenerator dont scrape sides of bacti-cenerator loop should be inserted toward the rear of the bacti-cenerator to avoid spattering. only insert the wire portion loop should stay in bacti-cenerator for atleast a full 5 seconds |
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what are the steps for preparing a smear from a broth culture?
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with sterile loop obtain one loop full of suspended cells
apply directly to glass slide and spread evenly over an area the size of a dime |
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what are the steps for preparing a smear from a plated specimen?
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place a small drop of water on the slide
sterilize loop cool loop touch the surface of a colony with a sterile loop avoid collection of large amount, the cells in a colony are very dense and numerous emulsify the cells in the water on the slide and spread evenly maintaing a size of a dime |
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what is the next step after allowing the slide to air dry for 5-10 minutes?
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heat fix the slide
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what is the purpose of heat fixation?
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prevents the specimen from washing off the slide
inactivates any enzymes present prevents cell from undergoing autolysis kills organism |
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How should heat fixation be conducted?
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grab slide with clothespin and place it on a warm (not hot) electric hot plate for 5-10 seconds
use clothespin to transfer slide back to your table and prepare to stain |
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what is a stain/dye?
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organic compound containing:
benzene-aromatic ring structure, colorless organic solvent chromophere-chemical group that imparts color to benzene chromagen (benzene + chromophere)-colored compound but is not a dye. it needs a + or - charge to bind. auxochrome-chemical compound that imparts ionization to the chromagen, this allows binding of the dye or stain to oppositely charged tissues or fibers chromagen + auxochrome = dye or stain |
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how do dyes or stains work?
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they bind to cellular components such as proteins or nucleic acids depending on the electrial charge
charge: acidic (-) basic (+) |
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are acidic stains anionic or cationic?
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anionic. when ionized they have a negative charge. bind to components of the cell with a positive charge
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are basic stains anionic or cationic?
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cationic. when ionized they have a positive charge. bind to cellular components with a negative charge.
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what are some examples of cellular components that would pick up a basic stain?
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DNA, RNA phospholipids, and other proteins are negatively charged
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which type of stain is used more frequently, acidic or basic? why?
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basic. most cells have a net (-) charge.
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what are some advantages of simple staining?
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"paints the cells" using 1 reagent
enhances contrast b/n cells and their surroundings allows visualization of morphological shape, arrangement, and size of the organism |
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what is the correct term for a cell whose morphology is spherical?
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coccus or cocci
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what is the correct term for a cell whose morphology is rod-shaped?
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Bacillus or bacilli
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what is the correct term for a cell whose morphology is spiral?
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Spirillum or spirilla
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what is the correct term for a cell whose arrangment is pairs?
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Diplo
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what is the correct term for a cell whose arrangement is chains?
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Strepto
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what is the correct term for a cell whose arrangement is random clusters?
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Staphylo
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what purpose do differential stains serve?
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allow bacteria to be seperated into "groups" based upon staining reaction (color) at the end of the staining procedure.
uses more than 1 color stain |
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what is the primary stain?
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the first reagent, colors all cells.
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what is the decolorizer?
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removes dye from some cells based upon certain cellular characteristics
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what is the counterstain?
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uses a contrasting color to the primary stain; stains cells that get decolorized.
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what are the 2 most common differential stains?
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gram stain and acid fast stain
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true or false: gram + cells only have a single layer of PPG
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false. has large amounts of PPG.
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what is the primary stain for gram stains?
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crystal violet, dyes all cells purple initially
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what is the decolorizer (95% ethanol)?
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lipid solvent and protein-dehydrating agent.
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what is the counterstain (safranin)
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stains the decolorized cells
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REVIEW PICTURES FROM NOTES
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!!!!!!!!!
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what might cause atypical gram stain results?
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old specimen
smear is too think/thin speciment is overdecolorized. |
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what are acid fast stains specidif for?
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Mycobacterium such as Mycobacterium tuberculosis
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what do gram - have that distinguish them from gram +?
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mycolic acids. these are the basis for the acid-fast reaction.
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what is the primary stain for acid fast?
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carbolfuchsin-stains all cells maroon/burgundy
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what is the decolorizer for acid-fast?
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acid alcohol-removes color from non-acid fast cells
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what is the counter stain for acid-fast?
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brilliant green. stainscells that are decolorized a teal/blueish color.not affected by counters tian
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REVIEW ALL PICTURES AND DIAGRAMS
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!!!!!!!!!
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what organism is responsible for tuberculosis?
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Mycobacterium tuberculosis
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what disease is caused the organism Mycobacterium leprae?
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leprosy a.k.a. Hansen's disease
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what is a differential stain?
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a stain which allows the bacteria to be seperated into groups based upon staining reaction (color)
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how many reagents are required in a differential stain? what are they?
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3
primary stain-colors all cells decolorizer-selectively remove dye from some cells counterstain-has a contrasting color to the primary stain and is used to stain cells or components decolorized by the decolorizer. |
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how many reagents are used in a gram stain and what are they? be specific.
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4
primary stain-crystal violet mordant-iodine. binds the crystal violet to the cells decolorizer-95% ethanol. lipid solvent and protein-dehydrating agent counterstain-safranin. |
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how many reagents are used in an acid fast stain?
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3
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what are they reagents used in an acid fast stain?
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primary stain-carbolfuchsin
decolorizer-acid alcohol counterstain-brillian green k |
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describe the steps of performing a gram stain
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obtain a slide and label it
sterilize inoculating loop prepare a smear of organism(s) allow slides to air dry for 5-10 minutes heat fix slide place slide on staining rack and flood with crystal violet, let stand 1 minute, rinse off slide flood slide with iodine and wait 1 minute, rinse decolorize with 95% ethanol drop wise while holding at an angle, dont over decolorize, rinse counterstain with safranin for 1 minute, rinse gently blot dry slide with folded kimwipe view under microscope clean all objective lenses before viewing other slides |
