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76 Cards in this Set
- Front
- Back
Focal point |
the point at which a lens focuses light rays |
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Focal length |
the length between the middle of the lens and the focal point |
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a shorter focal length means___ |
stronger magnification |
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compound microscope |
◦image formed by action of >2 lenses |
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the bright-field microscope |
produces a dark image against a brighterbackground |
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abilityof a lens to separate or distinguish small objects that are close together |
microscope resolution |
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shorterwavelength means ___ |
greater resolution |
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Why do we use oil in microscopy? |
to increase resolution and numerical aperture (light rays that did not enter the objective lens due to reflection and refraction will now do so) |
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working distance |
—distance between the front surfaceof lens and surface of cover glass or specimen when it is in sharp focus |
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In Fluorescence Microscopy, we expose specimen to ______ |
ultraviolet, light or blue light |
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In fluorescence microscopy, we stain the specimen with__ |
flurochromes to tag specific cell constituents foridentification of unknown pathogens |
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What type of microscopy allowsfor study of microbial morphology in great detail?? |
Electron |
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____ can determine actual in situ location of microorganisms in ecologicalniches |
Scanning electron microscope |
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to clean the oil lens, we can use___ |
xylene |
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Mannitol salt agar |
selective: for staphylococci differential: based on the release of acidic products |
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MacConkey Agar |
selective: for gram - |
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Blood agar |
Enriched: blood |
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Eosin Methylene blue Agar |
selective: for gram - differential: use of lactose/ sucrose as carbon/energy sources |
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What are fastidious organisms? |
Fastidiousorganisms:require specialized environments due to complex nutritional requirements. |
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Size of bacterial cells |
•0.2- 2.0 µm diameter •2– 8 µm length |
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What's a mordant? |
Mordant – intensify the stain ,increase the affinity of a stain for a specimen , to coat a structure to make it thicker and easier to see after it is stained
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Examples of simple stains |
Methylene blue , carbolfuchsin, crystal violet , and safranin
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capsulematerials are ____in water , and may be ____during intense washing |
soluble |
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Capsules appear as ___ surrounding stained bacteria |
halos |
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Bacteria that stain acid positive |
Mycobacterium & Nocardia and actinomyces |
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Acid positive bacteria contain |
mycolicacids |
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Hot stain is also called |
Ziehl–Neelsen Method (5% phenol in carbolfuchsin) |
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Cold stain is also called |
Kinyoun modification (15% phenol in carbolfuchsin) |
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Two medically important bacteria that form endospores |
Bacillus & Clostridia |
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•Bacteriacan form endosporesin approximately ____hours after being exposed to adverse conditions. |
6 to 8 |
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Young cultures of spore-forming microbes may not demonstrate any endospores because ______
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the vegetative cells may not have been subjected to sufficient stress to stimulate sporulation. |
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To improve the odds that spore formers can be detected, most methods suggest _____ |
using cultures that are 18 to 36 hours old |
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What's a wire loop made out of |
platinum |
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proper temperature in incubators |
37 for bacteria 28 for fungi |
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how do we clean petri dishes/ tubes/ infected material? |
put in autoclavable bags→into autoclave |
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how do we clean cotton swabs/ tips/ slides |
into a container containing disinfectant |
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BNR |
Basic nutritional requirements (C, N, H, O, P, S) |
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how much agar per 100 ml h20 |
1.5 gm |
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Nutrient broth ____gm/L |
13 |
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Nutrient agar ____ gm/L |
28 |
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Blood agar____gm/L |
40 |
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MacConkey agar_____gm/L |
50 |
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Autoclave heats at ___C for ____ minutes |
121 15-20 |
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Where does the autoclave get all that heat and pressure? |
from water vapor |
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Cholera agar is |
selective media for Vibrio cholera |
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SS agar is |
Selective for Salmonella and Shigella |
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what does salmonella cause |
typhoid |
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what does shigella cause |
dysentery |
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what color are salmonella colonies |
black |
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what color are shigella colonies |
yellow |
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chocolate agar is |
selective for Haemophilus influenzae and Niserria (meningitidis amd gonorrhea) |
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example of an acidic stain |
safranin |
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example of a basic stain |
methylene blue |
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Why do we do gram stains? |
for the gram rxn to see the size of cells to see the shape of cells (cocci, bacilli, curved, spiral) to see the arrangement of cells (chains, diploid, tetrads, clusters. single) |
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Treponema pallidum is |
a spiral shaped bacterium that causes syphilis |
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klebsiella pneumonia is |
a gram +, diplococci bacteria with a capsule |
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All cocci are gram + except |
nisseria |
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All bacilli are gram - except |
bacillus, diptheria, clostridium |
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Arrangement for bacilli |
single, stacks, chinese letter |
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what does clostridium cause |
gangrene |
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Differences between capsulated and non-capsulated bacteria |
capsulated is: resistant to phagocytosis more virulent has a store of nutrients and water can adhere more easily |
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3 Encapsulated bacteria |
klebsiella pneumonia, bacillus, streptococcus mutans |
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why do we air dry in capsule staining |
we don't want to dry out/ ruin the capsule |
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Stains of gram stain |
Crystla violet then safranin |
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Strains of capsule stains |
Congo red then acid fuchsin(2 min) |
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Fixative of capsule stain |
acid alcohol (1 min) |
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decolorizer of capsule stain |
h20 |
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steps of germintion |
activation, initiation, outgrowth |
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most important chemical compound in endospores |
calcium dipicolinate |
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Stains of endospore staining |
Malachite green (5-7min over b. h20) and safranin (2 min) |
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decolorizer in endospore stain |
h20 |
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fixative in endospore stain |
h20 |
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TB must be cultured on ____ for ___ |
Löwenstein–Jensen medium, |
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Stains in acid fast stain |
Carbolfuchsin(5min) then methylene blue (2mins) |
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decolorizer in acid fast stain |
acid alcohol |
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what can we see in sputum? |
epithelial cells streptococci dead WBCs M-TB |