Microscope

• reason why you stain a plant cell with iodine


  see the cell more clear/easier
• what do you use as a stain

  iodine
• why do we use the smallest magnification at first

  to get the whole cell in image
• practical

  1. place slide onto stage
  2. check if light works
  3. turn light on
  4. use lowest mag objective lens
  5. turn focus wheel until image is focused
  6. turn fine focus to get clear image
  7. turn objective lens to 10x
  8. refocus image with focus wheel
• light microscope

  light

  • provides color
  • portable
  • uses light
  • lower mag
  • lower resolution
  • cheap
  • small
  • no training needed
• electron microscope

  electron

  • uses beam of electrons
  • higher res
  • expensive
  • bigger
  • needs training
  • only black and white images
  • specimen has to be dead
  • higher mag
• differences between light vs electron

  light

  • lower mag than electron
  • lower res than electron
  • cheaper than electron
  • smaller than electron
  • no training needed whilst specialist training needed for electron
  • uses light whilst electron uses beam of electrons
  • provides color whilst electron only has b&w
  • specimen can be alive whilst electron has to be dead
• preparing a slide

  • add drop of water to clean the slide
  • grab thin onion layer
  • place onion tissue onto slide
  • use a stain
  • place cover slip by tilting up right and lower so it covers whole specimen and make sure no air bubbles to see the cell