8.1 Life is Cellular

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.

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.

Very Small Cell

Has Cell Membrane

Has DNA but no nucleus

Larger cell

Has a nucleus with genetic material - DNA

Has many structures and internal membranes that are specialized.