Cell Theory

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Cell Theory Mathias Schleiden(Botanist) 1838
Theodor Schwann (Zoologist) 1838

1. All organisms are made of cells
2. Cells are the smallest unit of living things.
3. Cells give rise to other cells.

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The Simple Microscope
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Anton Von Leeweunhoeke (1630s)
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Robert Hooke (1665)
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Compound Microscope
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Italian Compound Microscope, signed by François
Baillou, Milan, c. 1700.
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Compound Microscope (Modern)
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Images
Stomata of a plant
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Ameoba
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Compound Microscope Key Points

• Two lenses ( ocular and objective)
• The ocular magnifies the image from the
  objective.
• 2-D images
• can use live samples
• light must pass through sample to see it
• light source needed reflected by a mirror
  (old) or electric power
• 1000x at the most we have 400x as the highest
  mag. at school.
• Resolution and clarity is ok

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Electron Microscope
First one around 1930
First
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Two coccolithophores viewed under a scanning
electron microscope. Top Helicosphaera hyalina.
Bottom Discosphaera tubifera (Photos by Vita
Pariente)
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Transmission Electron (TEM)
DNA
Golgi body
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Scanning Electron(SEM)
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Pollen
Hookworm
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Weevil head
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Fern leaf cross section
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Black Widow spider claw
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Dentist Drill
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Electron Microscope Key points

• Electrons as a source to view sample image
  captured by computernot light.
• very specific magnification ( 1million x)
• Computer needed for precision and accuracy.

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SEM

• Sample coated with a metal ion
• Electrons shot over sample and scan across
• Electrons bounce off the surface and provide a
  3-D image
• Can view whole samples

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TEM

• Samples must be thinvery thin for electrons to
  pass through the sample.
• Cant be used to view whole or live samples
• Very good clarity and resolution
• 1 million x
• 2-D images very very detailed