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42 Cards in this Set
- Front
- Back
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Bacteria exhibits a great deal of diversity in their form, growth patterns, and nutrient preferences. However, where do they hold more diversity in? |
their biochemistry |
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During bacterial growth, they utilize various compounds in the medium like |
carbon, energy, and essential mineral nutrients |
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What alters the medium |
bacterial by products and wastes |
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during growth, what does bacteria do |
consume nutrients that are available and change the chemical nature of the medium |
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What is the first step in effective treatment |
identify the pathogen |
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Carbohydrate Fermentation |
Bacteria utilizes carbohydrates as an energy for metabolism
-ability to break down various carbohydrates (depends on the presence of certain enzymes in the cell)
-acid or possibly gas is produced |
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What are the three carbohydrate fermentation tests will we do in class |
-glucose -sucrose -lactose |
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what is the pH indicator solution used in a carbohydrate test |
Bromoscresol Purple |
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What tube is inserted in a broth tube that determines gas in a carbohydrate test |
Durham tube |
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What is a positive result for carbohydrate fermentation? |
-yellow color for acid producing -bubble in Durham tube for gas |
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What is a negative result for a carbohydrate fermentation test? |
-purple for no acid -no bubble in Durham tube for no gas |
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In all three carbohydrate fermentation tests what is the product |
production of acid changes the indicator from purple to yellow. If gas is produced it will rise to the top of Durham tube |
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What degree would incubate your specimens in a carbohydrate test |
37 degree Celsius |
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Starch Digestion |
-starch is a complex carbohydrate (polysaccharide) composed of glucose
-in order to utilize starch, bacteria must possess enzyme amylase which is capable of breaking the bonds liking the individual glucose molecules together |
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what type of agar do you use in a starch test |
starch agar |
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What solution do you use on the starch agar after the culture is allowed to grow |
iodine solution |
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What is a positive test for a starch test |
if their is starch digestion a lighter-colored or even clear zone will appear around the colonies
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What is a negative test for a starch test |
Starch will react to the iodine and produce a dark brown or black color |
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DNA Digestion |
DNA is a polymer composed of nucleotides
-a class of enzymes known a DNases are capable of breaking down DNA down into nucleotides |
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What agar do you use to preform a DNA test |
DNA agar which has DNA and methyl green, which is blue-green in color when associated to DNA |
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What is a positive result in a DNA test |
Faded color to clear because of the absence of DNA |
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What is a negative result in a DNA test |
DNA agar remains a bluish green |
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Catalase production |
In the course of a cell's normal metabolic activities, the compound hydrogen peroxide (H2O2) is often produce
-Hydrogen peroxide will normally break down into water and oxygen which is enhanced by the enzyme catalase |
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How do you detect the presence of catalase |
bacteria cultured on nutrient agar are exposed to hydrogen peroxide
If catalase is present, bubbles will immediately appear as oxygen is released |
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The appearance of bubbles in a catalase test is |
bubbles |
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What does SIM stand for |
Sulfur, indole, motility |
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What type of medium is used for a SIM test |
semi-solid nutrient agar that contains both iron and amino acid tryptophan |
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Why do you do the SIMs test |
-to determine whether hydrogen sulfide and indole are produced -to determine mobility
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H2S (Hydrogen sulfide) is produced by some bacteria when |
amino acid and cysteine is degraded by the enzyme cysteine desulfurase
-H2S turns to a black precipitation because of teh iron |
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positive for hydrogen sulfide in a SIM test |
black precipitation |
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What is indole produced from in a SIM test |
the degradation of the amino acid, tryptophan
-the enzyme tryptohanase is required for indole production |
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What is the indicator solution for indole in SIM tests |
Kovac's reagent after the bacteria has been cultured |
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what is a positive test for indole in a SIM test |
reddish color in the added Kovac's reagent |
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what is a negative result in motility in SIM test |
a strip of cultured bacteria |
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what is a positive result in motility in SIM test |
a turbid semisolid agar |
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Urea Digestion |
As proteins are processed in metabolism, urea is often generated as a byproduct.
Urea can be further degraded into ammonia |
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How is urea catalyzed |
by the enzyme urease |
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what does the broth contain in urea digestion |
urea |
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what is the indicator used in the urea digestion test |
phenol red |
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What is a positive urea digestion test |
if urease is present, the production of ammonia makes the solution more basic (alkaline) and turns phenol red to a pink or red color |
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what is the color of the inoculated urea digestion test |
peachy color |
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What is the color of a negative urea digestion test |
yellow, contains lower pH (acidic) |
