Microscopes

• Optical microscopes - use light to form an image

  • Limited resolution
  • Can’t be used to see all organelles
• Transmission electron microscopes = use electromagnets to focus a beam of electrons
• Scanning electron microscopes = Scan a beam of electrons across the specimen
• Advantages of TEMs:

  • High resolution images
  • Allows internal structures to be seen
• Disadvantages of TEMs:

  • Only thin specimens can be observed
  • Can’t produce a coloured image
  • Can’t observe live specimen
  • Lengthy preparation process
• Advantages of SEMs:

  • Used on thick or 3D specimen
• Disadvantages of SEMs:

  • Lower resolution than TEMs
  • Can’t be used to observe live specimens
  • Don’t produce a coloured image