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Microbiology Lab Final
Terms in this set (53)
A stain that uses only one stain
A stain that stains the bacteria
A stain that stains the background but leaves the bacteria unstained
A differential stain that allows you to classify bacteria as either Gram+ or Gram-
Who discovered the Gram stain?
Hans Christian Gram in 1884
Chemicals needed for gram staining
What does the decolorizing agent(alcohol) do to Gram- bacteria?
It dissolves the outer lipopolysaccharide layer, the CV-I(crystal violet-iodine) washes out through the thin peptidoglycan layer.
What color are Gram+ bacteria? Gram- ?
Primary stain for gram stain
Mordant for gram stain
Decolorizing agent for gram stain
Secondary stain for gram stain
Stain procedure done to test if the bacteria has mycolic acid(waxy lipid) in the cell wall. It is a differential stain
Who discovered the acid-fast stain?
Paul Ehrlich first discovered that Mycobacterium retained the primary stain even after being washed with acid-alcohol in 1882. The techniques were developed by Franz Ziehl, Fredrick Neelsen, and Joseph J. Kinyoun
Chemicals used for acid-fast stain
What color are acid-fast bacteria? Non Acid-fast?
Primary dye for acid-fast
Decolorizing agent for acid-fast
Counter stain for acid-fast
Used to identify and study the structure of bacteria
What chemicals are used for the Endospore stain?
Malachite green and safranin
What is different about the endospore stain compared to the other staining techniques?
You must places small bits of paper towels on the slides before applying the primary stain, when you apply the primary stain you have steam the slide for 5 minutes.
What color would endospores stain? Vegetative cells?
Endospores will be green and vegetative cells will be pink
The suffix -cidal
The suffix -static
Contains chemicals that prevent the growth of unwanted bacteria without inhibiting the the growth of the desired organism
Contains chemicals that enhance the growth of desired bacteria; other bacteria will grow, but the growth of the desired bacteria will be increased
Contains various nutrients that allow you to distinguish one bacteria from another by how they metabolize or change the media
selective and differential
isolates based on the ability to ferment lactose
inhibits the growth of Gram+ bacteria because of bile salts and crystal violet
Inhibits most bacteria due to salt
Staph will grow on this agar
due to change in pH, the color will change
Gram- bacteria will grow on this plate
will change to metallic because of high fermentation
What is a fermentation tube used for?
To detect acid and gas production from carbohydrates
What color is a neutral glucose, sucrose, or lactose tube?
What happens to the tubes if fermentation occurs?
The phenol red will turn yellow
How can you tell if gas was formed during fermentation?
There will be a gas bubble in the Durham tube
Why is an MRVP test used?
To determine if organisms produce acid from glucose or produce the neutral product acetoin.
How do you tell if the organism produced acid or a neutral agent?
You add methyl red
What does it indicate if methyl red remains in the MR?
The organism produced acid from glucose
If the methyl red turns yellow in the tube, what does it indicate?
Neutral products were produced
What is litmus milk?
Skim milk(caesin) and litmus
What is the litmus milk test used for?
To detect peptonization or catabolism
What occurred if litmus milk is clear after incubation?
peptonization(hydrolysis of the milk)
If the litmus milk is pink/purple....
catabolism of amino acids
What is the citrate test used to detect?
The removal(deaminase) of an amino acid(Phenylalanine)
What does green citrate mean? Blue?
There was no reaction
There was a reaction(Amino acid removed)
What does the SIMS test indicate?
Sulfide released from hydrogen sulfide reacting to metal
If the SIMS test results in a tan color, what does this indicate? But, if there is black percipitate?
Sulfide was not released
Sulfide was released due to the reactions between hydrogen sulfide and metal
What does the Indole test indicate?
If the bacteria converted tryptophan into indole
What do you add to the Indole solution to get the final results?
Red kovac solution results in....
Indole is present
indole is not present
incomplete hemolysis; the media will darken
complete hemolysis; clearing yellowing of the media
no hemolysis; the media is unchanged
Recommended textbook explanations
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Lehninger Principles of Biochemistry
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