Microbiology Lab final Flashcards

Terms Definitions
"foreign body"
What stains bacteria red?
Entamoeba histolytica
amoebic dysentary (bloody diarrhea)Asymptomatic carriers are the primary cause of spread
What is Barritts Solution B?
Bacillus cereus
Gram positiveEndospore stain- spore formingEMB- slight growthPEA- white growthMSA- small growth, yellowMacConkey- no growthNA plate- yellow growth
milder chemicals used to inhibit bacterial growth without hurting the skin
How are petri dishes stored?
bottoms up
What is capable of killing bacteria?
When studying wet mounts,What organism moved slowly?
Bacillus Cereus
What Destroys all microbial life, including endospores?
Staph and Strepto are Gram (+/-)
MacConkey Agar
used to isolate and differentiate members of the Enterobaceriaceae based on the ability to ferment lactoseContains bile salts and crystal violet inhibit growth of Gram-positive bacteria
Babesia species
Cause Texas cattle fever (transmitted by ticks)
A colony is a ________ of cells.
What color do gram positive and negative cells stain?
When studying wet mounts, which organism moved very quickly?
Pseudomonas aeruginosa
What is Protein + H20 + Gelatinase?
What are Agents that reduce microbial numbers numbers to a safe level?
Endo Agar
Used to detect fecal contamination in water and dairyContains color indicators sodium sulfite and basic fuchsin, which also act as gram positive inhibitors
Gram Stain
used to distinguish between gram pos and gram neg. The primary stain is crystal violet which stains both gram pos and gram neg bacteria.Gram's iodine is added as a mordant to enhance the crystal violet stainDecolorization occurs with the use of alcohol or acetone, only Gram negative cells are decolorized, gram positive cells are not.Safranin is used as a counterstain so that the gram negative cells can be colorized.
Naeglaria fowleri
Found in lakes and moist soilEnters through the nose and rapidly infects the brain and meninges.
The process of rendering a medium or material free of all forms of life.
What is added to nutrient medium to make it gel-like?
What is a sealed capsule that contains endospores of an organism and phenol red?
kilit ampule
Growth curve:
Lag phase- cells adapt to new surroundings no major growthLog phase- where growth outnumbers deathStationary phase- where they are equal (carrying capacity)Death phase- where more organisms are dying than reproducing.
What test uses Spirit Blue Agar Plate?
Fat Hydrolysis
What is nitrate broth used for?
Nitrate reductase test
What does citrate plus Citratase produce?
Oxaloacetate plus Acetate
What is used for studying the morphology of bacterial cells and characterizing some of the external structures, such as capsules, that are associated with bacterial cells
Negative stains
What is a Parallel arrangement of rod-shaped cells?
Palisade arrangement
What is the lowest powered objective? Highest?
What are two examples of negative stain dyes?
India ink
MSA plates are for what types of organisms?
Endospore Stain
used as a differential stain to detect presence and location of spores in bacterial cells
Each colony is a cluster of cells that originates from the multiplication of a single cell and represents the growth of a single species of microorganism. Such a defined and well-isolated colony is a____________.
pure culture
The snyder test is designed to meaure susceptibility to what?
Dental Caries
What is the microscope to be used when something measures in nanometers?
electron microscope
Citrate test
The ability to use citrate as the sole carbon source is detected by a change from green to deep blue. (bromethyl blue)
What test is used To determine the presence of oxidase enzymes?
Oxidase Test
What is lactose plus litmus milk tube?
Glucose + Glucose
What is a medium in which the components that make up the medium are not exactly known?
Complex medium
What are obligate anaerobes?
Bacteria that can't tolerate oxygen and must be cultivated under conditions in which oxygen is removed, otherwise they are killed
What is A surface of unglazed ceramic to find microorganisms by drawing them across the surface?
Streak plate
Viral life cycle (5 stages)
A- Adsorption- attach to cellI- infection- inject DNA/RNAR- replication- take over processesM- maturation- assemble its partsR- release- lyse the host cell
What is the device that is used as light source for the microscope?
the illuminator
What is the numerical value in a lens system that indicates the amount of clearance between the slide and the bottom of the objective lens?
working distance
Facultative Anaerobes
Dont need Oxygen but make use of it and grow more abundantly b/c oxygen is their final electron acceptor. (E.coli)
What is used to determine the ability of an organism to produce mixed acid end products from glucose fermentation?
Methyl red test
What is a medium made of a specific composition that is known?
Defined medium
The main functions of a microscope 
Resolution and Magnification of a compound microscope
Why isnt water used for electrophoresis? what is instead used?
because deionized water does not conduct current and no movement will occur. A buffer.
These are made from inert metals such as nichrome or platinum and are inserted into metal shafts that serve as handles.
Wire loops and needles
What is a virus that often causes a persistent infection to liver and can be spread by contact with body fluids?
hepatitis b virus
TSI- triple sugar iron medium contains:
three sugars: glucose, lactose, and sucrose.ph indicator: phenol rediron- to detect production of H2S
How does the hydrogen sulfide production test work?
Cystein plus water reacts with cysteine desulfurase to create pyruvic acid, hydrogen sulfide, and ammonia. Hydrogen sulfide then reacts with ferric ions to produce ferrous sulfide. The medium also contains glucose and lactose and phenol red as a pH indicator to show fermentation of these sugars. Gaps, cracks, or bubbles in agar indicate gas production
An oil immersion lense requires the viewer to ______. Its altogether magnification is
Put a drop of oil
in the membrane filtration analysis of water a FCC (fecal coliform count) was obtained by using what media
M-FC agar plate. this plate contains aniline blue to inhibit gram positive and bile salts to assure any growth is a fecal organism.
How is an effective dosage of antibiotics actually determined?
By using the Minimum Inhibitory concentration technique. where dilutions are done of the antibiotic and all tubes are innoculated. the tube with no growth and the minimum amount of antibiotics= correct dossage.
Name the two types of transfer agents used in this lab.
Transfer needle and transfer loop
What is a problem with hot-air ovens?
Dry heat doesn't penetrate materials easily and requires long periods of exposure
SIM agar deep test
In this test if the gas released is hydrogen sulfide it reacts with the iron in the medium to turn black.
What is the procedure for hydrogen sulfide production test?
Stab KIA with inoculum of organism
Incubate at optimum temperature
What is the procedure for the urease test?
Inoculate broth with the organism
Incubate at optimum temperature
How does hte methyl red test work?
Some organisms produce large amounts of various acids plus H2 and CO2. The large amounts of acids lower the pH to less than 5.0; These organisms also produce vast amounts of gas due to the presence of formic hydrogen lyase; Formic acid + formic hydrogen lyase = CO2 + H2
What is a streak plate?
A surface of unglazed ceramic to find microorganisms by drawing them across the surface
In the oral flora lab, besides the snyder test we used the TSY20B media plate (?) to isolate which bacteria?
Strep mutans.TSY= yeast extract 20= 20% sucroseB= bacitracin (inhibits other strep species)
Why is snyder test medium formulated?
To favor the growth of oral bacteria and discourage the growth of other bacteria
2 major causes of UTI's. how to test for it.
Proteus Vulgaris and Proteus MirabilisUrease test
What is the carbohydrate fermentation test used to determine?
Used to determine the ability of an organism to ferment a specific carbohydrate with or without the production of gas
Why do you want a thin smear?
The thickness of smears will determine if you can visualize individual cells, their arrangement, or details regarding microstructures associated with cells
On day two of the Enterotube lab we used what reagent and why?
Kovac's reagent for the indole test.
3rd step in culture transfer techniques for an 'aseptic transfer' of microorganisms.
A loop or needle is used for removal of the inoculum.
Which organism should not grow on a Crystal violet agar plate, why? Staph Aureus or E. coli
Staph aureus should not grow because crystal violet is a selective media for gram -ve bacteria. (e-coli should grow)
How do you interpret a motile test?
If the organism is motile, the tube will appear cloudy and usually the organism will spread over top of the media.
If the organism is non-motile the organism will grow along the streak line only; and the media will not be cloudy
Do you heat fix a negative stain before or after the dye?
Neither. No heat fixing negative stains
DNA agar plate was used in lab to isolate which species? why is it used?
Staph aureus;it can hydrolize DNA as a nutrient.
Why must you use a basic dye in a simple stain?
Bacteria are negatively charged and acidic dyes will not stain bacteria because of the electrostatic repelling forces involved
In gel electrophoresis how is it that we can see the DNA fragment moving across the gel?
We add a tracking dye (no longer use ethidium bromide)
What are the 7 steps of the spill procedure?
1. Notify everyone so they don't walk in it.2.Tell the teacher3.Flood spill with bleach4.Glove up5.Wipe up spill with paper towels, and then place in biohazard container.6.Wash hands.7. For spills on the body, use lysol soak and scrub with soap.
If given a MSA plate broken in 5 pieces and 2 show no growth. and of the three with growth 1 has made the plate yellow. what can you conclude?
The two that did not grow are not Stapylococcus.The two that grew but no yellow are staphylococcus but not maniotol fermenters.and the one that grew and changed to yellow is both and probably Staph Aureus.
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