optical microscope

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optical microscope

  1. 1. Microscopes Prof.ssa Patrizia Mauri ISISS “Cicognini-Rodari” - Prato
  2. 2. The first cells were observed by Robert Hook in 1632. They were cork cells. Then Antony van Leewenhoek observed many other kinds of cells. Obviously their microscopes were very rudimentary.
  3. 3. Visualizing Cells
  4. 4. Visualizing Cells <ul><li>Resolution - minimum distance two points can be apart and still be distinguished as two separate points. It depends on the type of radiation we use. Electrons give a larger resolution power. </li></ul><ul><li>O.M. ---> 0,2 micron </li></ul><ul><li>E.M. ---> 0,1 nanometer </li></ul><ul><li>Magnification – how many times the image is enlarged. </li></ul><ul><li>O.M. ---> 1.000–1.500 times </li></ul><ul><li>E.M. ---> 5.000-50.000 times </li></ul>
  5. 5. Optical Microscope Electron Microscope
  6. 6. Compound Optical Microscopes <ul><li>They use visible light. </li></ul><ul><li>They magnify the image in stages using multiple lenses (Objective and Eyepiece). </li></ul><ul><li>Also living cells and tissues can be observed. </li></ul>
  7. 7. O.M. Images Paramecium An unicellular alga Blood cells Leaf tissue
  8. 8. <ul><li>Two different types : </li></ul><ul><li>Trasmission Electron Microscope (TEM) </li></ul><ul><li>Scanning Electron Microscope (SEM) </li></ul>Electron Microscopes
  9. 9. TEM Transmission Electron Microscope Electrons are transmitted through the specimen to a photographic plate and we can observe the image on a monitor. The specimen has to be cut in very thin sections.
  10. 10. TEM Images A mitochondrion HIV- Viruses Muscle fibers Rickettsie
  11. 11. SEM Scanning Electron Microscope Electrons bounce onto the surface of the specimen and then are recorded on a photographic plate likewise a photographic scanner. ---> 3D image of cells, structures and surfaces.
  12. 12. SEM Images Human blood cells Pollen A lynphocyte HIV- Virus
  13. 13. Bacteria An arm hair Sperm cells on an egg RBC inside an artery

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