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38 Cards in this Set
- Front
- Back
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Colony |
group of microbial cells |
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What is the role of Agar? |
provides nutrients, minerals, and water for optimal growth |
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Ocular Lens |
lens you look through |
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Objective Lens |
lens closest to the specimen |
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Condensor Lens |
focuses light onto specimen |
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Iris Diaphragm |
adjusts amount of light that hits specimen |
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Resolution |
AKA - resolution power - for clarity |
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Why is oil used at 100x? |
to focus light and increase resoltion |
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Single celled VS Multicellular |
Single celled - morphologically and functionally identical Multicellular - cells are different than each other on same organism Ex. Rhizopus is multicellular |
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Why are microorganisms difficult to see in temp. wet mount? |
the cells have lack of contrast until stained |
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Yeast VS Mold |
Yeasts - microscopic and have oval cells Mold - macroscopic and have hyphae |
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What are the first two groups in the name of an organism? |
Genus and Species |
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Bacteria Names and Shapes |
bacillus- rod shaped coccus- round, small spirilla- spiral shaped Staph- cluster strepto- chain gram + - purple gram- pink |
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Describe aseptic technique |
1. disinfecting work space 2. flame occulation loops 3. sterile wound dressing |
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Name three reasons for heat fixing slides |
1. makes cells stick 2. kills cells 3. makes them more permeable to dye |
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Differential VS Structural |
Differential- Gram and Acid Fast stain Structural - flagella, endosproe, and capsule staining |
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Name the structures that cannot be seen without staining |
-cytoplasm -cell wall -ribosomes -flagella |
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What info about bacterial cells can be seen by using simple stain? |
You can see overall structure, cell shape, cell size, cell morphology, and arrangement |
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Gram + VS Gram - |
Gram + - has much thicker layer of PG, which traps stain better than thin layer of Gram - Gram - - alcohol rinse dissolves outer membrane causing them to lose stain |
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Iodine |
causes the crystal violet to form crystals in PG |
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Alcohol |
dissolves outer membrane causing them to lose outer crystals in PG |
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How can you tell if a Gram stain is pure or not pure? |
pure Gram stains will have only one color, pink or purple, if it is unpure both colors may be present. Usually due to cells dying |
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Why do Gram + cells dont decolorize in alcohol? |
Gram + cells have thicker layer of PG, so stain gets trapped in outer membrane |
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Name an acid fast bacterium |
mycobacterium tuberculosis |
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Give a one sentence description of differential stains |
They allow microbiologists to distinguish between different groups of bacteria based on the reaction to stain. |
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What non-microscopic technique could determine motility? |
Using a motility medium, motile bacteria are able to swim through agar and nonmotile bacteria only grow along inoculation line. |
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Why do dyes in capsule staining not interact with the capsule itself? |
capsules do not carry any charge, so they do not attract dye molecules. |
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List two pathogenic bacteria that can produce spores, and name the disease they cause |
Bacillus anthrasis - causes Anthrax Clostridium tetani - causes tetanus |
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Name the types of flagella and the shape |
Monotrichous - single flagella Lophotrichous - multi flagella from one end Amphitrichous - one flagella from each end Kophotrichous- multi flagella from both ends Perithrichous - multi flagella surrounding cells |
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Are bacterial endospores used for reproduction? |
No! Bacterial endospores are not reproductive |
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Describe why negative stains will stain backround but not cell |
Negative stains have a negative charge, and are repelled by the negatively charged cytoplasm, so they dye the backround and not the cell. |
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In a capsule stain, what is the role of simple stain and acidic stain? |
Capsules do not carry a charge, so they do not attract dye molecules. In capsule staining, a basic dye is used to stain the cytoplasm, then, an acidic dye is used to stain the backround, keeping the capsule clear |
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obligate aerobe |
needs oxygen to grow |
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facultative aerobe |
can grow with or without oxygen |
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obligate anaerobe |
cannot grow in presence of oxygen |
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aerotolerant anaerobe |
always perform anaerobic metabolism but are not killed in presence of oxygen |
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microaerophiles |
grow best in low concentrations of oxygen |
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Describe the different patterns seen when testing for growth in oxygen |
Aerobe- grows along top of tube, closer to O2 Facultative anaerobe - grows throughout tube, with higher concentration along top Aerotolerant - grows throughout tube, evenly Obligate anaerobe - grows at bottom of tube, farthest from O2 Microaerophile - grows in center of tube |
