Term
| why is end of test tube heated before and after transfer? |
|
Definition
| hot air current prevents settling of airborne bacteria into tube |
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Term
| explain how to 'fix' bacteria to slide. |
|
Definition
Broth
1. loop or 2 to slide
2. Air dry
3. Heat fix-3 times over flame
Solid media
1. Loop of distilled H2O on slide
2.add small amt. of org.
3. Air dry
4. Heat fix |
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Term
| what type of stains work on bacteria? what is methylene blue? |
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Definition
cationic or basic dyes(bact.neg.charged)
methylene chloride |
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Term
| what is the basic staining technique? |
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Definition
1. stain for 30sec - 2 min.
2.rinse
3.blot with bilbulous paper |
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Term
| explain diff. between RODAC and swab sampling technique? what does RODAC stand for? |
|
Definition
RODAC - agar filled to brim of plate, pressed directly to surface
Swab - sterile moist swab used to innoculate broth
Replicate Organism Direct Agar Contact |
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Term
| what are specialized biofilms made of prokaryotic photosynthesizers called? |
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Definition
|
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Term
| what is the process by which biofilms form? |
|
Definition
1. monolayer of polysachharides or glycoproteins adsorb to surface, allowing increasing chance ofbacterial attachment
2. reversible attachment of bact.to surface
3.transformation into irreversible attachment
4. Growth and division
5. Extracellular polymer substances produced
6. Passing particles trapped |
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Term
| What forces are responsible for reversible attachment of bact.in biofilms? |
|
Definition
| van der Waals forces and electrostatic attraction |
|
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Term
| what is the role of extracellular polymer substances in biofilms? |
|
Definition
| trapping of passing particles, enlargement biofilm |
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Term
|
Definition
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Term
| what types of microorganisms can be found in a Winogradsky column? |
|
Definition
| aerobic, anaerobic, microaerophilic, sulfate-reducing, methanogenic, photoautotrophs, cyanobacteria |
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Term
| what are two ways to test for motility? |
|
Definition
1. motility agar
2. hanging drop slide |
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Term
| Explain streak plate isolation. What is the drawback? |
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Definition
| 1. Streak plate isolation. Divide into 3 sections, flame loop between each new area. Only good for aerobic bacteria. |
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Term
| Explain the loop dilution method. What is the advantage? |
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Definition
Place one loopful of culture in tempered agar. transfer one loopful of this dilution in another tube of agar. pour each into a plate.
advantage is bact. grow within agar. works for anaerobes. |
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Term
| what 2 genes were included in the plasmid pGLO? |
|
Definition
1. green fluorescent protein
2.ampicillin resistance (beta lactamase) |
|
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Term
| what triggered the expression of green fluorescent protein in transformation experiment? |
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Definition
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|
Term
| what was used to make E.Coli competant for gene transformation? |
|
Definition
| heat and calcium chloride |
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Term
| how many microliters in a milliliter? in a liter? |
|
Definition
1000 microliter=1mL
1,000,000 microliters=liter |
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Term
| what is the difference between defined and complex media? |
|
Definition
defined - relatively pure chemicals in known concentrations
complex - components in unknown or variable concentrations, often extracts |
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Term
| what are three methods of laboratory supply sterilization? |
|
Definition
1. autoclave (steam pressure)
2. Oven (dryheat)
3. Filter sterilization |
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Term
| Which type of media has to be filter sterilized? Why? |
|
Definition
| Urea broth because urea will break down in autoclave at 15 psi |
|
|
Term
| what pH indicator used in lab titration? |
|
Definition
|
|
Term
| what organisms involved in yogurt fermentation? |
|
Definition
Streptococcus thermophilus (lactic acid production)
Lactobacillus bulgaricus (flavors/aromas) |
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Term
| What procedure is used to determine viable bacterial populations in dairy products in the US? |
|
Definition
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Term
| What type of bacteria is often a sign of utensil sanitation issues in milk production? what is unique about these organisms? |
|
Definition
| thermoduric bacteria, survive, but do not grow, at pasteurization temperature. affect shelf life |
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|
Term
| what is an example of an indicator organism used in water testing? |
|
Definition
| E.coli and Streptococcus faecalis |
|
|
Term
| what is a coliform bacteria? |
|
Definition
| a facultative anaerobic nonsporeforming gram negative rod that ferments lactose to produce gas. |
|
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Term
| what is the MPN method of water testing? reported in what form? what are the three levels of qualitative MPN tests? explain. |
|
Definition
Most Probable Number of coliforms/100mL
1.Presumptive:9 lactose (or lauryl tryptose) Durham tubes at volumes 10mL, 1mL, and 0.1mL. positive gas production results applied to chart.
2.Confirmed: colored growth on EMB agar
3. Completed:gram stain from innoculated nutrient agar slant AND acid/gas production in lactose broth |
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Term
| explain the nitrogen cycle. |
|
Definition
1.proteolysis:hydrolysis of proteins to form amino acids
2.Ammonification:ammonia seperated from amino acids or urea
3.Nitrification: oxidation of ammonium ions
4.Denitrification:reduction of nitrates to nitrites and nitrogen gas |
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Term
| Why were oatmeal and eggs added to Winogradsky columns? |
|
Definition
Oatmeal - Carbon source
Eggs - Sulfur source |
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|
Term
|
Definition
| a substance that intensifies color |
|
|
Term
| what are potential acid products of carbohydrate fermentation? what neutral products? what gasses? |
|
Definition
lactic, acetic, butyric, propionic acid
acetone, butyl alcohol, ethyl alcohol
CO2 and H |
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Term
| Name 2 complex carbohydrates. Name 3 disaccharides. Name 4 monosaccharides. |
|
Definition
Complex: cellulose, starch
Di:Maltose, sucrose, lactose
Mono:glucose, levulose, galactose, arabinose, fructose |
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