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| First person to see individual microorganisms. Made lenses that could magnify up to 100 to 300 times |
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| Technology of making very small things visible to the human eye |
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| Length of a light ray. Distance between two adjacent crests or troughs |
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| The ability to see two items as separate and discrete units |
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| Numerical measurement of the resolution that can be obtained with that lens |
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| A math expression relating to the extent that light is concentrated by the condenser lens and collected by the objective. |
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| If the light strikes and object and bounces back |
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| Passage of light through an object |
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| If light rays neither pass through nor bounce off on object, but are taken up by the object |
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| Absorbed light rays, especially UV light rays, are changed into longer wavelengths and reemitted |
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| If an object is only luminescent when light strikes it |
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| If an object continues to emit light when light rays no longer strike it |
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| Bending of light as it passes from one medium to another of different density |
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| Measure of the speed at which light passes through the material |
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| As light passes through a small opening, such as a hole, slit, or space between two adjacent cellular structures, the light waves are bend around the opening |
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| Refers to the use of any kind of microscope that uses visible light to make specimens observable |
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| Modern light microscope is descendent from whom? |
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Definition
| Hooke's compound microscope |
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Definition
| A compound light microscope(more than one lens) |
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Definition
| When changing from one objective lens to the next, the image is still be in nearly focus |
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| Bright field illumination |
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Definition
| An ordinary condenser in a light microscope causes light to be concentrated and transmitted directly through the specimen |
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Definition
| A microscope has a condenser that that prevents light from being transmitted through the specimen but instead causes the light to reflect off the specimen at an angle. Causing a light object to be seen on a dark background |
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| Phase contrast microscopy |
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Definition
| Special condenser and objective lenses that accentuate small differences in the refractive index of various structures within the organism |
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Definition
| Makes use of differences in refractive index to visualize unstained cells and structures. Produces much higher resolution than standard phase contrast |
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| UV light is used to excite molecules so that they release light of a longer wavelength that that originally striking them |
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| Fluorescent antibody staining |
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Definition
| Diagnostic procedures to determine whether an antigen is present. |
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| Transmission electron microscope |
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Definition
| Gives a better view of the internal structure of microbes than do other types |
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| Spraying a heavy metal over a specimen at an angle leaves a shadow where metal is not deposited, and produces images with a 3D appearance |
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| Technique to view interior of a cell. Cell is frozen then fractured to reveal the interior of a cell |
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Definition
| Involves evaporation of water from frozen and fractured specimen which exposes additional surfaces for examination |
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| Scanning electron microscope |
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Definition
| Used to create images of the surfaces of specimens, can resolve objects as close as 20nm giving magnif to approx 50K. Gives 3D views of exterior of cells |
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| Scanning tunneling microscopes |
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Definition
| Deep images, can be made using this technique, also movies can be used to examine live specimen |
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| Scanning tunneling microscopes |
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Definition
| Deep images, can be made using this technique, also movies can be used to examine live specimen |
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Definition
| Allows 3d imaging and measurement of structures. Useful in studying DNA because enables investigators to distinguish between bases . Can also measure forces |
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| microorganisms from a loopful of medium are spread onto the surface of a glass slide, can be used to view killed organisms. |
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Definition
After a smear is made, and allowed to air dry, it is quickly passed through an open flame. Accomplishes 3 things;
1. Kills organisms
2. Causes organisms to adhere to the slide
3. Alters the organisms so they more readily accept stains |
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| What are the most commonly used dyes in micro? |
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Definition
| Cationic or basic dyes such as methylene blue, crystal violet, safranin, and malachite green. These dyes are attracted to any negatively charged cell components |
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| What are some acidic/anionic dyes? |
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Definition
| Eosin and picric acid. They are attracted to positively charged cell structures |
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Definition
| Makes use of a single dye and reveals basic cell shapes and cell arrangements |
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Definition
| Makes use of 2 or more dyes and distinguishes between 2 kinds of organisms or between 2 different parts of an organism. Common ones are : gram stain, ziehl-neelsen acid-fast stain, and the schaeffer-fulton spore stain |
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Definition
Most frequently used differential stain
Bacterial cells take up crystal violet, iodine is added and helps retain the stain in certain cells. Those structures that cant retain crystal violet are decolorized when treated with ethanol-acetone solution, rinsed, and counterstained with safranin. |
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Definition
| A chemical that helps retain the stain in certain cells |
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Term
| Ziehl-Neelsen Acid-Fast stain |
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Definition
| Can be used to detect TB and leprosy causing organisms of the genus Mycobacterium. Acid fast retain bright red color. This is due to the lipid components of cell wall |
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Definition
| Used when a specimen or part of a specimen resists taking up a stain. Stains the background around the organism, and organism remains clear and stand out. A differential stain can be used to demonstrate the presence of the cell inside the capsule |
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Definition
| Too thin to be seen easily with the light microscope. coat the surfaces of flagella with dye or a metal such as silver |
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Term
| Schaeffer-Fulton spore stain |
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Definition
| Endospore walls are very resistant to staining, so a special technique must be used. Heat fixed smears are covered with malachite green and then gently heated until they steam. ~5 minutes of this steaming makes walls more permeable to the dye |
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