Term
| What is the most important stain in bacteriology? |
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Definition
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Term
| What kind of stain in the Gram stain? |
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Definition
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Term
| How are cells identified using Gram staining? |
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Definition
| Identified by their respective colors, purple and pink to red after performing the staining method. |
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Term
| Gram positive bacteria retain ... through decolorization with ... |
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Definition
a crystal violet-iodine complex
alcohol or acetone |
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Term
| What color do gram-positive bacteria appear? |
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Definition
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Term
| For gram-negative bacteria, ... removes ... |
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Definition
alcohol or acetone
crystal violet-iodine |
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Term
| What is the counterstain? |
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Definition
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Term
| What color do gram-negative bacteria appear? |
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Definition
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Term
| What is the primary stain? |
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Definition
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Term
What is the mordant?
What does it do? |
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Definition
Iodine
It complexes with the crystal violet and forms an
insoluble complex in gram positive bacteria. |
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Term
| How do cells appear after the primary stain? |
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Definition
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Term
| How do cells appear after the mordant? |
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Definition
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Term
| What is the decolorization step? |
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Definition
| The dye-mordant complex is leached from gram negative cells by alcohol or acetone. |
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Term
| Is the dye-mordant complex removed from gram positive bacteria? |
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Definition
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Term
| How do cells appear after the alcohol step? |
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Definition
Gram positive: purple
Gram negative: colorless |
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Term
| What does the counterstain do? |
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Definition
| It stains the gram-negative cells. |
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Term
| Why is the appearance of the gram positive cells unchanged? |
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Definition
| Because the crystal violet is a much more intense stain than safranin. |
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Term
| What is the cell wall of gram positive bacteria made of? |
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Definition
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Term
| What is the cell wall of gram negative bacteria consist of? |
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Definition
| An outer membrane that covers a much thinner layer of peptidoglycan. |
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Term
| How old should the cultures be when gram-staining? |
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Definition
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Term
| Do gram positive bacteria convert to gram negatives? |
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Definition
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Term
| Can gram negatives convert to positives? |
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Definition
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Term
| Which is the most critical step in the gram-staining technique? |
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Definition
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Term
| How is the decolorization step crucial? |
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Definition
| If too much alcohol is used, the dye mordant complex can eventually be removed from gram positives and convert them to gram negatives. |
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Term
| How long should the crystal violet be applied? |
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Definition
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Term
| How long should Gram's iodine be applied? |
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Definition
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Term
| How long should the alcohol be applied? |
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Definition
| 10-20 sec or until solvent flows colorlessly. |
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Term
| How long should the safranin be applied? |
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Definition
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Term
| What kind of gram is S. aereus? |
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Definition
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Term
| What kind of Gram is E coli? |
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Definition
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Term
| What kind of Gram is Serratia? |
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Definition
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Term
| What kind of Gram is Proteus? |
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Definition
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Term
| For differential staining, how does a counterstain differ from a primary stain? |
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Definition
| The counterstain must be of a different color. |
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Term
| What color are bacterial endispores after a Gram stain? |
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Definition
Colorless
because
stains don't penetrate spores. Resistent! |
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Term
| What makes Mycobacterium particularly resistant to staining? |
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Definition
| The peptidoglycan layer with mycolic acid. |
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Term
| What kind of Gram is Mycobacterium? |
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Definition
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Term
| The endospore coat is made of ... |
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Definition
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Term
| Endospores are produced by bacteria in the genus... |
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Definition
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Term
| Acid-fast staining is useful for identifying the causative agent of ... |
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Definition
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