Term
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Definition
| Nutrient material prepared for the growth of microorganisms |
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Term
| Criteria for culture medium |
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Definition
| Moist, nutrient rich, proper pH, O2 needs, sterile, incubated at proper temperature |
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Term
| To support growth, media... |
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Definition
| Must contain an energy source |
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Term
| Examples of energy sources in media |
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Definition
| Carbon, nitrogen, sulfur, phosphorus, other organic growth factors |
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Term
| Chemically defined medium |
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Definition
| Exact chemical composition is known |
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Term
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Definition
| Routine media, not all components known |
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Term
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Definition
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Term
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Definition
| Grows anaerobes, reducing media |
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Term
| Selective differential media |
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Definition
| Suppresses growth of unwanted microbes, encourages growth of desired microbes |
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Term
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Definition
| Easier to distinguish colonies of the desired organism |
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Term
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Definition
| Purple because of sugar (lactose), inhibits gram-positive, lactose fermentators turn pink |
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Term
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Definition
| Using a flame-loop and a plate already containing the bacteria, streak the 1st section of a clear plate. Sterlize the loop by flaming, stick it in a clear part of your plate to cool it, take bacteria from the 1st section and use it to streak the 2nd section. Repeat for the 3rd and 4th sections of your plate and flame the loop again at the end. |
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Term
| 3 methods for preserving bacterial cultures |
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Definition
Refrigerating
Deep Freezing
Lyophilization |
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Term
| What is the refrigeration method for preserving bacterial cultures good for? |
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Definition
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Term
| Describe the deep freezing method for preserving bacterial cultures |
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Definition
| Suspend in liquid and quick freeze at -50 to -90 deg C. Culture can then be thawed, put in broth and plated. |
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Term
| Described the lyophilization method of preserving bacterial cultures |
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Definition
| Freeze-drying method - quick frozen then water is removed. Turns into a powderlike residue that can be stored for years and revived w/ the addition of liquid. |
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Term
| What is bacterial division? |
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Definition
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Term
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Definition
| Cell elongates and replicates DNA, CW/CM begin to grow inward, CW meets, 2 identical cells are made. |
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Term
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Definition
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Term
| What does plate counts use to determine cell growth? Direct or indirect? Example? |
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Definition
| CFUs, direct, serial dilutions |
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Term
| Disadvantages to plate counts? |
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Definition
| Time, there is a limit to colonies on the plate, too many can overcrowd/hinder growth of some |
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Term
| Describe how to do a serial dilution |
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Definition
| Take a sterile broth of bacteria and dilute it successively to obtain a small concentration of bacteria, then plate it using a flamed loop and incubate |
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Term
| Describe the pour plates method for determining cell growth. Direct or indirect? |
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Definition
| Direct - add 1 mL of bacterial broth to a sterile petri dish, pour warmed nutrient medium into dish w/ gentle agitation, incubate when agar solidifies, colonies grow w/in the medium and on the surface |
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Term
| Disadvantages to plate pouring? |
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Definition
| Some bacteria damaged by melting agar, no distinctive colonies, no further studies on colonies under agar, less water in the media if sample is greater than/= to 5 mL |
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Term
| Describe the spread plates method for determining cell growth |
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Definition
| Spread inoculum evenlly on surface of agar w/ a bent sterile glass rod and sterile glass beads |
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Term
| Describe filtration method for determining cell growth |
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Definition
| Take a thin membrane filter (pores), place on petri dish w/ bacteria on it, incubate |
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Term
| When is the filtration method used? Direct or indirect? |
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Definition
| When bacteria count is very small/water sources; direct |
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Term
| Describe direct microscipic counts method for determining cell growth |
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Definition
| Bacteria suspension put on a slide marked in cm^2, special slide allows for # of bacteria in several fields to be counted |
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Term
| What are some disadvantages of direct microscopic counts? |
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Definition
| Difficult to count motile bacteria, counts dead cells, high #s of bacteria needed |
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Term
| What are some advantages of direct microscopic counts? |
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Definition
| Don't have to wait for bacteria to grow |
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Term
| Describe the spectrophotometer method of determining cell growth |
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Definition
| Measures turbidity, the amount of light scattering is directly proportional to the biomass of the cell which is INDIRECTLY related to cell # |
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Term
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Definition
| A collection of methods of contorl of microbial growth whose goal in particular is the prevention of unintended transfer of pathogenic microorganisms |
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Term
| Circumstances/conditions/microorganism that will generally result in less effective antimicrobial action |
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Definition
| Insufficient nutrients/cold temps/unclean surfaces/insufficient exposure/TB |
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Term
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Definition
| Preventing/arresting the growth of microorganisms (as living on tissue); chemical that doesn't work against endospores/viruses |
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Term
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Definition
| Removal of microorganisms from the skin |
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Term
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Definition
| Cleaning of pathogenic microorganisms from inanimate objects |
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Term
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Definition
| use of aseptic techniques |
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Term
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Definition
| exclusion of pathogenic organisms |
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