Microsopy

Studying Cells

  • Microscopes let us see things that we can't see with the naked eye. The microscopy techniques we use have developed over the years.
  • Light microscopes use light and lenses to form an image of a specimen and magnify it. They let us see individual cells and large subcellular structures, like nuclei.
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Studying Cells

  • Electron microscopes use electrons instead of light to form an image. They have a much higher magnification than light microscopes.
  • They also have a better resolution. (Resolution is the ability to distinguish between two points, so a higher resolution gives a sharper image).
  • Electron microscopes let us see much smaller things in more detail, like the internal structure of mitochondria and chloroplasts. They even let us see tinier things like ribsomes and plasmids.
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Required Practical

  • If you want to look at a specimen under a light  microscope, you need to put it on a microscope slide first.
  • A slide is a ***** of clear glass or plastic onto which the specimen is mounted.
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Required Practical

  • Add a drop of water to the middle of a clean slide.
  • Cut up an onion and seperate it out into layers. Use tweezers to peel of some epidermal tissue from the bottom of one of the layers.
  • Using tweezers, place the epidermal tissue into the water on the slide.
  • Add a drop of iodine solution. Iodine solution is stain. Stains are used to highlight objects in a cell by adding colour.
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Required Practical

  • Place a cover slip on top. To do this stand the cover slip upright on the slide next to the water droplet.. then carefully tilt and lower it so it covers the specimen.
  • Try not to get any air bubbles under there - they'll obstruct your view of the specimen.
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Required Practical

  • Clip the slide you've prepared onto the stage.
  • Select the lowest-powered objective lens.
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