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14 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Why do we look at unstained slides? |
It allows us to observe living microbes, which can include motility |
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Why do we stain bacterial cells? |
It allows us to distinguish details such as bacterial shape, arrangement, and size. |
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Principle of staining |
Unlike charges attract and similar charges repel |
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What charge do bacteria have? |
Negative |
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Dyes |
Salts composed of a cation and an anion |
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Cation |
A positively charged ion |
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Anion |
Negatively charged ion |
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Chromophore |
The part of the dye molecule that is brightly colored |
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General types of dye |
1. Basic dyes 2. Acidic dyes |
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Basic dyes |
Most common dyes used in lab Chromophores are positively charged |
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Acidic dyes |
Chromophores are negatively charged |
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Examples of basic dyes |
1. Methylene blue 2. Safranin 3. Crystal violet |
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Examples of acidic dyes |
1. Acridine orange 2. Nigrosin |
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Heat Fixing |
The process of quickly passing a slide over flame 3 times This functions to evaporate the waxy layer on the slide that repels water and interferes with staining |
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