BIO 244 – Lab Exam 3 – Flashcards
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Unlock answers| What is thermal death time? How do we test for it? What was the most resistant organism? |
T.D.T = Temp and time required to kill an organism
Hot water bath exposure for increments of time.
Bacillus subtillus due to sporulation |
What agar medium was used for the Ultra Violet experiment? What was tested for? What was the most resistant? What was least resistant? |
Nutrient agar The sensitivity levels of organisms to ultra violet radiation. Bacillus due to the ability to sporulate. E. Coli - died instantly |
| What agar was used for the thermal death time experiment? |
| Nutrient broth |
What is the purpose of a Standard Plate Count?
How is it done? |
It's a technique used to figure out how much bacteria is suspended in a liquid. ; The medium containting organisms is diluted and inoculated into an empty agar plate. Then pour plate agar is poured and mixed with the inoculated dilution. Once it hardens, incubate and count the number of colonies and multiply that by the dilution factor. This will give you CFU's/ml |
| What is a machine that helps count colonies when there are too many to count when performing a standard plate count? |
| Quebec Colony Colony Counter |
| What is Litmus Milk? What does it test for? What do the results usually look like? |
A complex medium that can potentially distinguish among many species of bacteria
If gas is produced during fermentation, you may be able to see bubble or cracks in the milky medium Pink = Lactose is fermented Blue = Lactose is not fermented will become alkaline Curddling (a solid) = protein may be digested. Peptonization = results in a clear (not milky) because the casein may be metabolized all the way down to individual amino acids Reduction = The litmus may be and become colorless. The culture will then look milk white.
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| What tests are used to recreate anaerobic conditions or low oxygen concentration environments? |
| Thioglycollate and Brewer Jars |
| What is Thioglycollate? What are the profiling resuts? |
Thioglycollate is used to test the aero tolerance of bacteria. Strict aerobes will only grow in the oxygen-rich top layer Strict anaerobes will only grow in the lower areas of the tube. Microaerophiles will grow in a thin layer below the richly-oxygenated layer. Facultative anaerobes can grow throughout the medium but will primarily grow in the middle of the tube, between the oxygen-rich and oxygen-free zones. |
| How does Thioglycollate produce these varying oxygen concentrations? |
| Oxygen levels through out the medium are reduced from the sodium thioglycollate. This produces different ranges in oxygen levels as distance increases from the surface of the tube towards the bottom. |
| What is a Brewers Jar? |
| A container where cultured plates are stacked and maintained in anaerobic conditions or microaerophilic conditions. |
| What organism was a strict anaerobe? What organism was a facultative anaerobe? What organism is a strict aerobe? |
Strict Anaerobe = Clostridium Difficile Facultative Anaerobe = E. Coli & Enterococcus Strict Aerobe = Pseudomonas aeruginosa |
What is the Nitrate Broth Test?
What organisms succesfully reduced to Nitrite? ammonia? |
tests for the reduction of Nitrate.
E. Coli = Nitrite Pseudomonas = Ammonia |
What was the purpose of the Snyder's medium Test? ; What did we inoculate with?; What do the results mean? |
It was to test for the presence of Lactobacillus Inoculated with Saliva Looks for pH change. ; Green = Negative ; Yellow = Positive |
| What's the difference between a disinfectant vs an antiseptic? |
A Disinfectant is a chemical that is utilized on non-tissue surfaces to kill any organism it comes into contact with. It's non specific in killing ability ; An antiseptic is the same except that it can be used on live tissue surfaces. |
| What does the term Dimorphic mean? |
| Mold can convert to yeast and vice versa depending on temperature and nutrient conditions. |
| What indicates Mold is in its asexual stage? |
| The presence of spores (canidiophores) |
| What indicates Mold is in its sexual stage? |
The combination of two Hyphii + and - strains. |
| What is an indication asexual stage in yeast? |
budding; ; new yeast cells bud from parent cell. |
| What is an indication of the sexual stage of reproduction in Yeast? |
| Fusion |
| What are the two samples of Yeast observed in lab? |
| Candida and Pneumocystis |
| What are the two examples of Mold that were examined in Lab? |
| Apergillus and Penicillium |
| What type of medium was in the agar plate for the take home culture? |
| Suberodextrose Agar |
| What stain is used to identify molds? |
| Lactal Phenol Blue |
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| Pencillium |
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| Aspergillus |
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| Aspergillus |
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| Candida |
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| Candida |
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| Pneumocystis |
| What is a disc diffusion analysis? |
It's a technique used to test different disinfectants/antiseptics to determine how sensitive an organism is to it.
A disc is loaded with disinfectant/antiseptic. It's placed in the middle of an agar plate that's been completely covered in organism. After incubation, you examine for any clearing of organism around the disc or lack thereof. You measure the diameter from one side of the clearing to the other. The larger the clearing, the more sensitive the organism is to the chemical |
| What is MIC? |
Minimum Inhibitory Concentration
It's the smallest amount of drug/chemical needed to illicit a response. |
| What is the zone of inhibition? |
| The clearing around a disc. |
What is tecnique called for the Antibiotic test? ; What was the medium/plate used called? |
Kirby-Bauer Test ; Mueller-Hinton Plate |
| What were the 3 generally good antibiotics? |
| Cefalotaxime, Amikacin, and Erythromycin |
| What are factors that increase UV radiation resistance? |
| Sporulation and the presence of enzymes that repair damaged DNA (Rec A). |
| What type of organisms does SNyders medium allow growth for? |
| Microaerophils |
| What reagent is used in the Nitrite test if reagent Sulfinic Acid and Alpha Naphalymine don't produce a color change? |
| Zinc |
| What color does the medium turn in a Nitrate test if it's positive for Nitrite? |
| Red |
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