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39 Cards in this Set
- Front
- Back
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What are the two types of streaking?
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Direct or positive staining procedure (Cell takes up positvely charged dye and is stained)
Indirect or Negative staining procedure (Cell is Immersed in negatively charged dye) |
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What is an example of Direct staining?
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Methylene blue
Crystal Violet Safranin |
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What is an example of Indirect staining?
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Nigrosine
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What are the steps of a gram stain process?
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1. Add cells with drop of water to slide.
2. Heat fix 3. Crystal Violet 4. Iodine 5.Alcohol 6.Safranin |
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What is the function of Crystal Violet in the gram staining process?
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Primary stain: will stain both gram negative and gram positive purple.
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What is the function of Iodine in the gram staining process?
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Mordant: Increases the binding affinity of the stains. Forms large CV-I complexes with crystal violet.
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What is the function of alcohol in the gram staining process?
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Decolorizing agent: Causes gram positve cell walls to shrink, sealing in the crystal violet. Causes gram negative cell wall to dissolve making it clear.
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What is the function of Safranin in the gram staining process?
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Counterstain: Stains gram negative cells pink to allow viewing.
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What is the purpose of a streak plate?
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To produce colonies of bacteria from a suspension of cells
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What is an endospore?
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A dormant form of bacteria that can survive harsh conditions.
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What is sporulation?
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The process of spore forming within the mother cell.
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How are endospores different from vegetative cells?
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They are different than the vegetative cell in that they are dormant and metabolically inactive, do not replicate and can survive for a long period of time.
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What is Germination?
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The activation of a dormant cell to its normal metabolically active state. It breaks down the layers of endospore cote releasing the DNA, proteins, etc, which can begin replication.
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What are the steps of an endospore stain?
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1. Prepare slide
2. Heat fix 3. While heating slide, stain with Malachite green. 4. Allow to cool. This traps dye in endospore. 5. Wash with water to remove dye from vegetative cells. 6.Counterstain vegetative cells |
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What are the parts of a flagellum?
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1. Long helical filament – function as the propeller
2. Hook (short curved structure) – attaches the filament to basal body 3. Basal body – embedded in the cell surface, and function as the rotary motor that drives the attached hook and flagella. |
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What types of movement do flagella support?
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Swimming: Run or Tumble
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What can one learn from a motility stab?
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Whether an organism is motile or non-motile. If motile there will be growth (red coloring or cloudy) around the site of innoculation.
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What is General Growth Media?
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Designed to support the growth of a broad range of organisms
Contain usable forms of C, H, O, P, N, S and trace elements. Will not support organisms with specific “growth factors” Fastidious organisms – organisms that require enriched media with specific ingredients. |
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What is Complex media? What is an example of complex media?
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Media made of complex constituents and undefined mixture, digested proteins, and extracts of yeast. Provide a mixture of nutrients. Also known as “rich” since there are many multiple source of nutrients.
Trypticase Soy Agar is a good example |
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What is a Defined media?
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A media where all of the constituents are quantified.
Glucose Minimal Salts broth is a good example; contains glucose as only carbon source |
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What is a Minimal media?
Example? |
medium using minimal requirements for growth, usually a defined media as well.
Glucose minimal media; contains only glucose |
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What is a Selective media?
Example? |
A media that permits the growth of one bacteria while prohibiting the growth of another.
Simmons Citrate Agar; Contains citrate as the sole carbon source. Only bacteria that can use it will grow |
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What is a Differential media?
Example? |
A media that allows visual differentiation between two or more species of bacteria.
Blood Agar; differentiates bewtween different types of hemolysis |
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What media is selective and differential? Why?
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MacConkey's
Selective: Only gram negative can grow Differential: Bacteria that ferment lactose will appear pink, those that don't will appear white. |
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What is a Pyschrophile?
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Organisms that thrive in cold temperatures. 0-15 degrees
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What is a Mesophile?
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Organisms that thrive in normal temperature (body temp). 20-45 degrees
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What is a Thermophile?
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Organisms that thrive in hot temperatures. 55-70 degrees
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What is a Hyperthermophile?
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An organism that thrives in extremely hot temperatures. 70+ degrees
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What is a Halophile?
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Bacteria that require relatively high salt concentrations (10-20%) for growth.
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What is a salt tolerant organism?
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An organism that does not require salt for growth but may grow in its presence.
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What is an aerobe?
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An organism that requires oxygen for life
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What is an anaerobe?
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An organism that cannot grow in the presence of oxygen
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What is a facultative anaerobe?
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An organism that can grow with or without oxygen
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What is a microaerophilic organism?
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An organism that requires low oxygen concentrations for growth
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What does Simmons Citrate Agar test indicate? What does a positive test look like?
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A positive test will turn the medium blue. Indicates that the organism can use citrate as sole carbon source
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What is a catalase test? What does a positive test tell you?
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Adding peroxide to cells on a slide. Bubbling indicates a postive result. Catalase positive means the cell can break down toxic products of oxygen
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What can does an oxidase positive result indicate?
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That the organism has an electron transport chain with cytochrome oxidase.
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CFU/mL formula?
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# colonies counted (CFU) x dilution factor / Volume plated (ml)
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What is a positive result for Carbohydrate Utilization media?
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Acid produced = Yellow
Gas produced = Bubble in durham tube |
