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Microscopy - Coggle Diagram

- - - - EXAMPLE: iodine in potassium iodine solution is used to stain starch grains in plant cells.
      - EXAMPLE: eosin is used to make the cytoplasm show up.
  - - - TEMs
        
        ADVANTAGES: give high resolution images, so shows small objects.
        
        DISADVANTAGES: can only be used on thin specimens. can only be used on non-living specimens.
        
        TEMs use electronmagnets to focus a beam of electrons, which is then transmitted through the specimen. denser parts of the specimen absorb more electrons, which makes them look darker on the image you end up with.
      - their maximum resolution is about 0.0002 micrometres
      - they use electrons to form an image. they have a high resolution meaning they can see organelles in a lot of detail.
      - SEMs
        
        ADVANTAGES: can be used on thin specimens. can be 3D
        
        they scan a bean of electrons across the specimen. this knocks off electron from the specimen, which are gathered in a cathode ray tube to form an image. the images you end up with show the surface of the specimen and they can be 3D
        
        DISADVANTAGES: gives lower resolution images than TEMs. can only be used on non-living specimens.
      - they have a maximum useful magnification of about ×1500000.
      - they produce black and white images.
    - - you cant use them if the organelle is smaller than 0.2 micrometres. this includes ribosomes, ER and lysosomes.
      - they use light to form an image. they have a maximum resolution of about 0.2 micrometres.
      - the maximum useful magnification of an optical microscope is about ×1500.