Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell....
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Transcript of Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell....
![Page 1: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/1.jpg)
Microscopes
The invention of the microscope in the 17th century led to the discovery of the cell.
Robert Hooke described cells using this light microscope.
![Page 2: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/2.jpg)
Modern Microscopes
• Visible light is focused on the specimen with the condenser lens.
• Light passing through the
specimen is refracted with
an objective and an ocular
lens (magnify and invert the
image for the observer).
![Page 3: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/3.jpg)
Two Important Properties of Microscopes:
• Magnification – how much larger an object is made to appear.
• Resolving power – minimum distance between two points that can still be distinguished as two separate points.
*limited by the wavelength of light.
*maximum resolution of a LM is 0.2μm.
*highest magnification is 1,000X.
![Page 4: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/4.jpg)
Gallery of Cells
What can you infer about function from the structure of these cells?
![Page 5: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/5.jpg)
Cell Theory
![Page 6: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/6.jpg)
Electron Microscopes
• Instead of light, electron microscopes use electron beams which have much shorter wavelengths (resolving power of 0.2nm).
• Enhanced resolution and magnification led to the identification of subcellular organelles.
• There are two types of electron microscopes: transmission and scanning electron microscopes.
![Page 7: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/7.jpg)
Transmission Electron Microscope
• Electromagnetic lenses.
• Electrons transmitted through the specimen are
focused onto a viewingscreen or film.
• Used to study internal cellular structure.
![Page 8: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/8.jpg)
TEM Images
![Page 9: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/9.jpg)
Scanning Electron Microscope• Electron beam scans the surface of the
specimen.
• Excites secondary electrons on sample.
• Collects secondary electrons and focuses onto a viewing screen.
• Great depth of field – 3D image.
![Page 10: Microscopes The invention of the microscope in the 17 th century led to the discovery of the cell. Robert Hooke described cells using this light microscope.](https://reader036.fdocuments.us/reader036/viewer/2022062517/56649f165503460f94c2be0c/html5/thumbnails/10.jpg)
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