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Chapter 3 Section 1 Microscopes
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Units of Measure Metric system of measurement International System of Measurement SI Base Unit is the Meter (m) Kilometer = 1,000 m (2/3 of a mile) Centimeter =.01 m (1/2 diameter of penny) Millimeter =.001 m (width of pencil tip) Micrometer =.000001m (bacteria cell) Nanometer =.000000001 m (water mol.)
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Light Microscopes Light passes through one or more lenses to produce an enlarged image of a specimen
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Electron Microscopes Forms an image of a specimen using a beam of electrons rather than light 3 Types Transmission electron microscopes (TEM) Scanning electron microscope (SEM) Scanning tunneling microscope
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Micrographs The image produced by the microscope Type of microscope Magnification Name of object Light Microscope 320 magnification Amoeba
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Magnification & Resolution Magnification Makes the image appear larger than its actual size Resolution A measure of the clarity of an image High magnification & good resolution are needed to view details of extremely small objects clearly.
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Limitations of Microscopes Light microscopes: lower magnification power but can view LIVING cells Electron microscopes: higher magnification but cannot view living cells
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Light Microscope Ocular lens - closest to the eye Objective lens - closest to the specimen Both magnify 40x objective & 10x ocular = 400x magnification
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Electron Microscopes Can magnify 200,000x Both electron beam and specimen must be placed in a vacuum chamber Living cells cannot be viewed 3 Types Scanning Electron Microscopes (SEM) Transmission Electron Microscopes (TEM) Scanning Tunneling microscopes
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Scanning Electron Microscope Specimen is coated with a thin layer of metal 3-D image of cell surfaces Black & white image that can be artificially colored
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Thin metal coating
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SEM of Human Blood
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Foot of a House Fly SEM x300
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Transmission Electron Microscope Cross section of specimen Non living Stain with metal ions Electrons pass through specimen & form image Image is in black & white (Can be enhanced with color)
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Corona Virus (TEM)
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Cytoplasm of Liver Cell (TEM)
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Bacteriophages (TEM)
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Golgi Apparatus (TEM)
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Scanning Tunneling Microscope 3D image of the specimen’s surface Can be used on living organisms
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Scanning Tunneling Image
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