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65 Cards in this Set
- Front
- Back
Anton Van Leeuwenhoek
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first to observe live microorganisms
known as the father of microbiology made improvements to the 1st microscope and got 300X magnification |
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most of pathogenic fungi are
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dimorphic
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micrometer
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is equal to 0.000001m
micro indicates that the unit following should be divided by 1 million |
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nanometer
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is equal to 0.000000001m
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1 meter equals how many centimeters
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100 cm
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1 metere equals how many micrometers
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1000 micrometers
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1 micrometer equals how many nanometers
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1000 nanometers
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Size of Protozoa
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100 micrometers
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Size of Yeast
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8 micrometers
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Size of Bacteria
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1-5 micrometers
(some are much longer than wide) |
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Rickettsia
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0.4 micrometers
intracellular bacterium, gram negative |
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Chlamydia
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0.25 micrometers
causes syphillis |
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Mycoplasma
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0.25 micrometers
gram negative causes variety of pnemonia, urinary tract infections |
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bacteria contains both
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DNA and RNA
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Viruses contain
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DNA OR RNA
never both |
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compound light microscope
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has a series of lenses and uses visible light to observe specimens
uses white light |
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magnification
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ocular lenses and objective lenses
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resolution
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AKA resolving power
is the ability of the lens to distinguish fine detail and sructure |
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Resolution for a light Microscope
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0.2 micrometers
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Contrast
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stains change refractive index
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refractive index
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a measure of the light bending ability of a medium
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as you go up in magnification, what do you need to adjust
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light, need more of it and adjust it by using substage iris diaphgram lever
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as magnification goes up, what happens to the lenses
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they get smaller which is why we have to add more light
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immersion oil
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has same refractive index as glass
helps us preserve the direction of light rays at the highest magnification |
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brightfield microscope
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what we use, simplest of all optical microscope illumination
dark objects appear against a bright background |
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darkfield microscope
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used to examine live microorganisms, objects are visible against a dark background
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What microscope should you use to view spirochetes?
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darkfield microscope
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spirochete
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a corkscrew shaped bacterium with axial filaments, type of spirilla bacteria
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Treponema pallidum
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spirochete that causes syphillis
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Borrelia burgdorferi
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spirochete that causes lyme disease
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Fluorescence Microscope
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absorbs UV light and emits visible light, used a lot in clinical labs
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immunofluorescence
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a diagnostic tool using antibodies labeled with fluorochromes and viewed through a fluorescence microscope
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the smaller the wavelength
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the higher the resolution
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prokaryotes
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have no cell organelles
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electron microscope
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uses electrons and electromagnetic lenses to view specimens, there are 2 types
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2 types of electron microscopes
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scanning electron
transmission electron |
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transmission electron microscope
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a electron microscope that provides high magnification 10,000-100,000X of thin sections of a specimen
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scanning electron microscope
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an electron microscope that provides 3D views of a specimen magnified 1000-10,000X
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staining
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simply means to color the microorganism with a dye that emphasizes certain structures
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fixing
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in slide prep: the process of attaching the specimen to the slide
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smear
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thin film of material containing microorganisms spread over the surface of a slide
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Technique for preparing a slide for light microscopy
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1) Smear
2) Air Dry 3) Heat Fix |
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Basic Dyes
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cationic chromophore
(positive charged) |
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Acidic Dyes
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Anionic Chromophore
(negative charged) |
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Chromophore
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stains are salts composed of positive and negative ions, one of which gets colored called a
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Negative Staining
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a procedure that results in a colorless bacteria against a stained background
the bacteria repels the stain |
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3 types of staining techniques
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simple
differential special |
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simple stain
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uses a single basic dye and sometimes a mordant
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mordant
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substance added to a staining solution to make it stain more intensely
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type of mordant we will commonly use
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iodine
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differential stains
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twp types
react differently with different types of bacteria and can be used to distinguish them |
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types of differential stains
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acid fast stain
gram stain |
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Differential Stains use what type of dye?
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basic dye
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gram stain
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differential stain that classifies bacteria into 2 groups: gram positive and gram negative
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gram positive
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bacteria that retain the color of the primary stain after the alcohol attempts to decolorize it
stains a dark purple or violet |
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gram negative
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bacteria that loses the dark violet or purple color after decolorization
stains pink |
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Steps to make a gram stain
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1) heat fixed smear is covered with a primary stain, a basic purple dye
2) Dye is washed off, mordant is added 3) Slide is washed with a decolorizing agent 4) Alcohol is rinsed off and stained with a basic red dye |
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negative staining is used for
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bacteria with capsules, which is a slime layer around the bacteria
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Acid Fast Stain
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a differential stain used to identify bacteria that are not decolorized by acid-alcohol
cells that retain a basic stain in the presence of acid alcohol |
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which dye can be used as a simple stain?
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any basic dye
usually methylene blue, safranin, crystal violet |
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Acid Fast Stains are used to identify what type of bacteria
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myobacterium
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Special Stains
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used to color and isolate specific parts of microorganisms
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Negative staining for capsules
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uses basic stain and negative stain to test for the presence of a capsule
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flagella staining
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requires a mordant to make the flagella wide
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endospore stain
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heat is required to drive the stain into it
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