Magnification and microscopes

• Light microscopes


  Lower magnification

  Lower resolution

  Cheaper and easier to use

  Live specimins
• Transmitted electron microscope


  Complex fixation

  Vacuum (dead specimens)

  Inside cell organelles

  2D (thin)

  Complicated
• Scanning electron microscope


  3D picture

  Vacuum (dead)

  Complicated

  Outside of cells
• Magnification formula


  Image size= real size*magnification
• Electron microscopes


  Higher resolution (0.1 nm)

  Shorter wavelength than visible light

  Beam of electrons instead of a beam of light
• Prepare a slide


  1. Peel a thin layer of tissue (allow light through)

  2. Place a drop of water on the slide (prevent dry out)

  3. Place tissue sample on slide

  4. Add iodine to stain starch and help distinguish organelles

  5. Add cover slip at an angle

  6. Lower slowly using a needle (avoid air bubbles)