Electron microscopes

• How do transmission electron microscopes work?

  • Beam of electrons passes through the sample used to create an image
  • focused using electromagnets
  • 2D, black & white image produced
  • can see internal ultrastructure of cell
  • structures absorb electrons and appear dark
• Complete the following to evaluate TEMs.

  • Highest resolving power
  • high magnification
  • extremely thin specimens required
  • complex staining method
  • specimen must be dead
  • vaccum required
• How do scanning electron microscopes work?

  • Beam of electrons pass across sample used to create image
  • focused using electromagnets
  • 3D, black and white image produced
  • electrons scattered across specimen producing image
• Complete the following to evaluate SEMs.

  • High resolving power
  • high magnification
  • thick specimens usable
  • complex staining method
  • specimen must be dead
  • vaccum required