NOTES: 7.1 - Introduction to the Cell

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NOTES 7.1 - Introduction to the Cell
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Cell Theory

• All living things are composed of 1 or more
  cells.
• Cells are the basic unit of structure function
  in living things.
• New cells are produced from
• existing cells.

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MICROSCOPES

• Light Microscope
• Electron Microscope (1940s)
• Scanning Electron Microscope
• Transmission Electron Microscope

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Light Microscope

• works by passing visible light through a thin
  section of specimen and then through glass lenses
• magnification about 1000x - 1500x

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Electron Microscope (1940s)

• uses electron beams which have shorter
  wavelengths of light (so you can see smaller
  objectsmore detail)
• magnification up to 500,000x

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Electron Microscope

• Scanning Electron Microscope
• electron beam scans the surface of a specimen
• useful for studying the surface of specimen in
  3-D
• Transmission Electron Microscope
• electrons transmitted through specimen
• used to study internal cell structure

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Disadvantages to EM

• can only view dead cells (preparation steps kill
  living cells)
• very expensive

zooxanthellae cells cultured from coral Aiptasia
pulchella in a Scanning Electron Microscope
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Cell Types Classification!
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ALL CELLS

• have a cell membrane
• have cytoplasm
• have ribosomes
• can reproduce contain genetic material

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CELLS CAN BE CLASSIFIED AS

• 1. PROKARYOTES
• 2. EUKARYOTES

See no nucleus!!!
See a nucleus!!!
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NUCLEUS

• membrane-bound organelle in eukaryotic cells
• contains the cells DNA
• enclosed by a nuclear envelope
• contains all of the information for cell to
  function