Test Bank for Bailey and Scotts Diagnostic Microbiology 14th Edition by Tille
Chapter 06: Role of Microscopy
Tille: Bailey & Scott’s Diagnostic Microbiology, 14th Edition
- In microscopy, resolution can be defined as the:
|b.||extent to which detail in the magnified object is maintained.|
|c.||ability of objects to stand out from the background.|
|d.||ability to see objects against a black background.|
The extent to which detail in the magnified object is maintained is called resolution.
- Contrast in microscopy is most commonly achieved by:
|a.||changing objectives for various specimens.|
|b.||increasing the resolution or resolving power.|
|d.||adding a blue filter to the light path.|
Various staining techniques are used to increase contrast and make objects appear more visible.
- The first step in the Gram-stain sequence is the application of _______, which is the primary stain.
Crystal violet is the primary stain used in the Gram-stain sequence.
- A mordant that is applied after the primary stain to bond chemically the alkaline dye to the bacterial cell wall is:
Gram’s iodine serves to stabilize the crystal violet in the cell wall of gram-positive bacteria.
- After which step in the Gram-stain procedure are gram-positive bacteria first distinguished from gram-negative bacteria?
Up until the decolorizer step, all bacteria and cells appear the same during the Gram-stain procedure.
- The acid-fast stain is specifically designed for bacteria whose cell walls contain:
Mycolic acids render the bacterial cells resistant to decolorization and thus cause acid-fast organisms to maintain the primary stain in the acid-fast staining procedure.
- In the Kinyoun acid-fast staining method, ______ replaces _____ in the primary stain solution.
|a.||increased phenol; heat|
|b.||heat; increased phenol|
|c.||mycolic acid; heat|
The Kinyoun method is one in which the heat step of the traditional acid-fast staining method is replaced by increased phenol.
- Of the different types of staining and microscopic techniques, which one of the following is basically the most sensitive?
Fluorescence makes the object appear bright against a dark background, making it easier to see on low magnifications.
- The fluorochrome stain that can be used to detect mycobacteria is:
The mycolic acids in the cell walls of mycobacteria have an affinity for auramine and rhodamine.
- The fluorochrome stain used to study a fungus is:
The cell walls of a fungus will bind calcofluor white.