Cards (7)

  • What does TEM stand for?

    Transmission electron microscope
  • How do they work?
    they project an electron beam through a sample.
  • Are the images 2D or 3D?

    2D
  • Why are some parts of the image dark and other light ?
    Denser tissue appears darker in the micrograph, here electrons are eaily absorbed. In less dense areas the electrons can easily pass through, making them appear lighter.
  • What's an advantage of them?
    Very high-resolution images.
  • What are the limitations?
    Must be performed in a vacuum, so cannot be used to visualise living material. Can only be used for thin tissues.
  • What are the role of heavy metals in TEM?
    Heavy metals 'stain' sample by creating contrast.