Questions and Answers
What are chromophores?
Chromophores are color-bearing groups of stain.
Why do acidic dyes not stain bacterial cells?
Acidic dyes are negatively charged and therefore repelled by negatively charged bacterial cells.
Crystal violet is an example of what type of stain?
Crystal violet is a basic stain which has a positive charge.
Volutin is composed of what?
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What is meant by palisade arrangement of cells?
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What is the difference between basic and acidic dyes?
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What shape does Vibrio cholerae have?
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Where are the fusiform bacteria usually found in humans?
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Study Notes
Chromophores
- Chromophores are groups in stains responsible for imparting color.
Acidic Dyes
- Acidic dyes carry a negative charge.
- They are repelled by the negatively charged surfaces of bacterial cells, preventing them from staining these cells.
Crystal Violet Stain
- Crystal violet is classified as a basic stain due to its positive charge.
Volutin
- Volutin is primarily composed of polyphosphate, a compound significant in cellular biochemical processes.
Palisade Arrangement of Cells
- Refers to a parallel arrangement of rod-shaped cells typical of corynebacteria.
- This arrangement can be visualized using dark field microscopy, which resembles negative staining techniques.
Basic vs. Acidic Dyes
- Basic dyes carry a positive charge and attract negatively charged bacterial cells, allowing for effective staining.
- In contrast, acidic dyes do not adhere to bacterial cells due to charge repulsion.
Vibrio cholerae Shape
- Vibrio cholerae is recognized for its distinct comma shape (curved rod).
Fusiform Bacteria
- Fusiform bacteria, characterized by their spindle shape, are commonly found in the human gut and oral cavity, playing a role in normal flora and bacterial interactions.
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Description
This quiz delves into the fundamentals of simple staining in microbiology. It covers key concepts such as chromophores, the action of acidic dyes, and the characteristics of common stains like crystal violet. Test your understanding of how staining techniques are employed in laboratory settings.
