Electron microscopes

• Transmission Electron Microscope (TEM)

  electron gun produces beam of electrons that is focused onto specimens by electromagnets. parts of specimen allow electrons to pass through
• Advantages of TEMs

  higher res than SEMs
• Limitations of TEMs

  Living specimens cannot be observed

  Image is not in colour

  Specimens must be extremely thin

  Complex staining method
• Scanning Electron MIcroscope (SEM)

  directs a beam of electrons onto surface of specimens from above. electrons are scattered by the specimen
• Advantages of SEMs

  Specimens do not need to be as thin

  Produces 3D images
• Limitation of SEMs

  Living specimens cannot be observed

  Complex staining method