Microscopy

• Parts of a microscope

  A) Objective lens

  B) Eyepiece lens

  C) Stage

  D) Light source

  E) Turret

  
• What is the max magnification for a light microscope?

  1500x
• What is the max magnification of an electron microscope?


  500,000
• What is the magnification formula?

  magnification = image/actual
• What is resolution?


  The ability to distinguish separate points on an image as two separate objects
• Why do electron microscopes have a higher resolution than light microscopes?

  Electrons have a smaller wavelength than visible light
• How to prepare a wet mount slide slide:

  • Wear gloves to avoid staining
  • Use scissors to cut a sample of the tissue
  • Use a scalpel to peel off a layer of tissue from the sample
  • Place on a slide
  • Apply a stain
  • Add a coverslip
• What is a graticule?

  A small disk with an engraved ruler
• How does a TEM microscope work?

  Electron beams passes through sample and produce a 2D image
• What is the resolution of a light microscope?


  200 nm
• What are wet mount slides used for?

  Living specimens
• What is the resolution of a TEM microscope?


  0.5 nm
• What is the resolution of a SEM microscope?


  3-10 nm
• What is the magnification of a TEM microscope?


  500,000x
• What is the magnification of a SEM microscope?

  300,000x
• What are the benefits of a TEM microscope?

  High resolution images
• What are the benefits of a SEM microscope?

  Can produce 3D images & can be done on thick specimens
• What are the negatives of an electron microscope?

  Its expensive, its harder to use, can only use non-living specimens
• What are the negatives of a SEM microscope?

  It has a lower resolution than a TEM microscope
• What are confocal microscopes?

  • Flood specimen with beam of light (laser) instead of white light
  • Specimen is stained with fluorescent dye
  • When laser is shown on specimen, dye gives off a light
  • The light is focused through a pinhole to a detector
  • The detector is connected to a computer which generates an image
  • Images can be 2D or 3D
• Benefits of confocal microscopes:

  • High resolution
  • Can be used on thick specimens
  • Images can be 2D or 3D
• Limitations of confocal microscopes:

  • Expensive
  • Harder to set up/use
  • Laser can damage specimens
  • Time-consuming