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Smear Preparation
Smear Preparation
18
Microbiology
10/23/2011

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Cards

Term
What are the goals of a good smear?
Definition

1. cause cells to adhere to the slide so they're not washed away during subsequent staining/washing

 

2. shrinkage of cells does not occur

 

3. thin smears

Term
How does one prepare a smear if the bacteria are growing in a liquid medium?
Definition
Place 2 or more loopfuls of the liquid medium directly on the slide
Term
How does one prepare a smear if the bacteria grow in solid medium?
Definition
Place 1 or 2 loopfuls of water on the slide and then use an inoculating loop to disperse the organism in the water.
Term
How much material one needs to make a good smear from solid medium?
Definition
Very small amount.
Term
What is the purpose of heat fixation?
Definition
It kills the cells so they adhere to the glass and don't get washed away.
Term
What causes a stain to adhere to bacterial cells?
Definition
The positive charge of the edge will adhere to the negative charged cell surface structures.
Term
Why kind of dyes won't adhere?
Definition
Acidic dyes.
Term
In which staining technique a basic dye is used?
Definition
Simple, capsule
Term
In which staining technique a stain that does not penetrate cells is used to color the background?
Definition
negative, capsule
Term
Which staining technique is useful for visualizing spirochaetes?
Definition
negative
Term
Which type of staining technique is useful for visualizing the glycocalyx of certain bacterial species?
Definition
capsule
Term
In which staining technique are cells mixed with a stain before they are smered on the slide?
Definition
negative, capsule
Term
In which staining technique is heat fixation of the slide not recommended?
Definition
negative
Term
In which staining technique is water used to remove excess stain from the slide?
Definition
Simple, capsule
Term
Which substances can one use for the simple stain procedure?
Definition

Crystal violet

methylene blue

Term
What can one use for the negative stain procedure?
Definition

India ink

Nicrosin

Term
Before heat fixation, a wet smear of bacterial cells on a slide must first be ...
Definition
air-dried.
Term
Bacterial capsules can consist of ...
Definition

polysaccharides

polypeptides with unique amino acids