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  • Created by: Jasmin
  • Created on: 17-09-13 18:59
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  • Microscopy
    • 1 m
      • 10-3m - millimetre
        • x1000
          • 10-6m - micrometre (um)
            • x1000
              • 10-12m - picometre (pm)
    • Object: material placed under microscope
    • Image: appearance of this material as viewed
    • Magnification: process of enlarging something only in appearance, not in physical size
      • Magnification = size of image/size of object IAM
    • Resolution: ability of a microscope or telescope to distinguish between images/features that are close together
      • Greater resolution greater clarity in image
    • size of object = size of image/bar length x bar scale
    • Light microscope
      • Max resolving power: 200nm
      • Magnification: up to x2000
      • Specimens
        • Living or dead
        • Thin sections of tissue easily prepared 1um in thickness for good detail
      • Image
        • Staining not necessary so real colours can be observed
        • Staining allows colour images
      • Cost: within budget of individuals and schools
    • Electron microscope
      • Adv
        • Electron beam has short wavelength and microscope can resolve objects well - high
        • Electrons are negatively charged the beam can be focused using electromagnets
      • Max resolving power: 2nm
      • Magnification: up to x500000
      • Scanning (only looks at surface, no detail of inside)
        • Speciman
          • Dead
          • Must be thin
          • Image
            • Slow down electron beam hits secondary detector produces sharper image of high resolution in 3D
            • Staining using metal necessary - gold cheapest form coating
            • black and white but false colours can be added by photographic technique
      • Short wavelength than light microscope
      • Cost: within budget of unis and research labs only
      • Transmission (can see through) best resolution
        • Image
          • Produced on screen, can be photographed to give photomicrograph (photo of image produced by microscope)
          • In bw complex staining process required uses heavy positive ions for staining
        • Speciman must be thin allow electrons to penetrate


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