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24 Cards in this Set
- Front
- Back
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Simmon's citrate agar (SCA)
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medium in which sodium citrate is the only carbon source; ammonium phosphate is the only nitrogen source
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What must a bacteria have to grow in Simmon's citrate agar?
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Citrase (enzyme) in order to break down citric acid.
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Identify the chemical reaction that occurs in SCA when a bacteria with citrase is present.
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What color must the SCA turn in order for a reaction to have occurred?
Is it acidic or basic? |
SCA must go from green => blue and it is basic.
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Sulfide-Indole-Motility agar (SIMs)
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medium that detects indole production, sulfur reduction to H2S, and motility of bacteria
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What process must SCA go through for it to turn basic?
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Bacteria must go through the original process, and then through the ammonium phosphate breakdown process above.
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urease
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enzyme that breaks urea down into CO2 and ammonia
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urea
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waste product of animals
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What occurs during the urease test?
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An increase in the concentration of ammonia (from the breakdown of urea) leads to an increase in pH.
A color indicator shows when the solution turns basic, light orange => hot pink. |
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In the SIMs agar and TSI agar test, what color appears when H2S is produced?
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Black
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Identify the 3 sugars contained in Triple Sugar Iron agar.
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Glucose
Lactose Sucrose |
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Where is the slant of the tube w/ agar?
Where is the butt of the tube w/ agar? |
Slant = at the top, where the agar slants
Butt = bottom of tube, where it curves |
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If glucose is fermented, what happens to the TSI agar?
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The agar becomes acidic and turns yellow in color.
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If glucose is fermented and so is lactose and sucrose, what happens to the TSI agar?
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The agar will STAY acidic.
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If glucose is fermented but NOT lactose and sucrose, what happens to the TSI agar?
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Bacteria will degrade amino acids and proteins and the agar will become alkaline and turn red in color (butt will stay yellow).
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What will a bacteria use if it can't use any of the sugars in the TSI agar?
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Peptone
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A bacteria that is _________ uses peptone and will have a red slant and yellow butt.
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A bacteria that is AEROBIC uses peptone and will have a red slant and yellow butt.
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A bacteria that is _________ uses peptone and will have a red slant and red butt.
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A bacteria that is AEROBIC AND ANAEROBIC uses peptone and will have a red slant and red butt.
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Gas production in TSI agar is noted by... (3)
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Cracked agar
Agar has raised in tube Bubbles present in agar (+) |
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What is added to SIMs agar to test for indole?
What reaction are we looking for? |
3-4 drops of Kovac's reagent
Red color means (+) reaction |
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Explain how you would assess each test according to the agar it is in.
TSI (Triple Sugar Iron) Slant Butt Gas H2S |
Slant = If yellow, mark A; if red, mark K
Butt = If yellow, mark A; if red, mark K Gas = (+) if shows signs of gas production; 0 for neg. reaction H2S = If tube turns black, (+) reaction; 0 for neg. reaction |
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Explain how you would assess each test according to the agar it is in.
SIM (Sulfide Indole Motility) H2S Indole Motility |
H2S = If tube turns black, (+) reaction; 0 for neg. reaction
Indole = (+) if Kovac Reagent turns it red. Motility = (+) if movement away from stab line; |
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Explain how you would assess this test according to the agar it is in.
SCA (Simmons Citrate Agar) = Citrase |
(+) reaction if tube turns blue
0 (neg. reaction) if tube is still green. |
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Explain how you would assess this test according to the agar it is in.
Urea = Urease |
(+) reaction if tube turns bright pink
0 (neg. reaction) if tube is still light orange |
