8.1 Life is Cellular

8.1 Life is Cellular

The Discovery of the Cell

• 1600's - Cells were discovered

• 1665 Robert Hook looked at cork under the microscope and coined the word "cell" because they reminded him of tiny rooms

• 1838 Matthias Schleiden concluded that all plants are made of cells.

• 1839 Theodor Schwann stated all animals are made of cells

• 1855 - Rudolf Virchow stated all cells can only come from the division of existing cells.

• Many biologist confirm the cell theory.

Exploring the Cell

• Light Microscope - Uses light to pass through a specimen and uses two linses to form an image. Can magify up to 1000 times. Can see cells and cell structures

• Electron Microscopes - Uses beams of electrons focused by magnetic fields. Magnifies up to 1 billionth. Can see viruses and DNA molecules. Two types:

• Transmission Electron microscopes - see two dimensional images.

• Scanning Electron microscope - see three dimensional images.

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Prokaryotes

• Very Small Cell

• Has Cell Membrane

• Has DNA but no nucleus

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Eukaryote

• Larger cell

• Has a nucleus with genetic material - DNA

• Has many structures and internal membranes that are specialized.