18 Questions
What is the primary reason for staining microorganisms in microscopy?
To resolve the problem of microorganisms appearing colorless
What is the composition of stains?
A mixture of a cation and an anion
What is the role of the chromophore in a stain?
It is the unsaturated group of molecules capable of producing color
Why are basic dyes more frequently used for staining bacteria?
Because the colored cation is attracted to the negatively charged bacterial cell
What is the result of using acidic dyes for staining bacteria?
The background is stained, but the bacteria are not
What is the purpose of negative staining?
To observe the shape and size of the bacteria
What is a neutral stain composed of?
A complex salt of a dye acid with a dye base
What is the term for a compound that contains a chromophore?
Chromogen
What is the net charge of bacteria at a pH of 7?
Slightly negative
What can be seen more easily using negative staining?
Overall cell shape, size and capsules
What type of ion is the chromophore in an acidic dye?
Anion
Why do basic dyes bind to bacterial cells?
Because the bacterial cell is negatively charged
What is the name of the complex salt of a dye acid with a dye base?
Neutral stain
What is the term for an unsaturated group of molecules that produces color?
Chromophore
What is the purpose of staining microorganisms?
To make the microorganisms visible under a microscope
What is the result of using a basic dye on a bacterial cell?
The bacterial cell is stained
What type of charge does a bacterial cell have at pH 7?
Negatively charged
What is the term for a compound that contains a chromophore?
Chromogen
Learn about the importance of staining in microbiology, different staining procedures, and the composition of stains. Understand how stains help to visualize microorganisms under bright-field microscopy.
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