Method of studying cells

• What is magnification?

  • How much bigger the image is than the specimen
• What is resolution?

  • Minimum distance apart between 2 objects in order for them to be seen as seperate items
• What are artefacts?

  • What you can see down the microscope that aren’t part of the cell e.g fingerprints
• How does a light/optical microscope work?

  • Wavelengths of light
• What are the advantages of an optical microscope?

  • Cheaper
  • Can use live specimens
  • Can take colour images
• What are limitations of an optical microscope?

  • low resolution / magnification
• How do electron microscopes work?

  • Using beams of electrons
  • Electrons negatively charged and magnets used to focus the microscope
  • electrons absorbed or deflected by particles in the air and therefore a vacuum needs to be used
• What are the types of electrons microscopes?

  • Transmission (TEM)
  • Scanning (SEM)
• What are the disadvantages of an electron microscope?

  • Take long time to prepare- more likely to get artefacts
  • Very expensive
  • Can’t use live organisms- vacuum
  • Doesn‘t produce images in colour
• What is the description of a TEM?

  • High resolution
  • 2D images
  • Thin sample needed
• What is the description of SEM?


  • High resolution, but not as high as TEM
  • Produces 3D images
  • Can use thicker sample
• How do you calculate magnification?

  Magnification=image size/actual size