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sience chapt 2 sect 2
cell theory 1
all organisms are made of one or more cells
cell theory 2
the cell is the basic unit of organization in organism
cell theory 3
all cells come from cells
made the first microscope
light microscope, image viewed against bright background; most often used to study cells; up to 2,000x
image bright against dark background; up to 2,000x; details more visible than brightfield
up to 250x; historic, handheld, clear images of "beasties"
up to 1,500x; specimen must be treated with special flourescent stain; certain cell structures and substances glow
Transmission electron microscope
aims a beam of electrons through specimen; up to 1,000,000x
emphasizes differences in specimen's capacity to bend light waves; good for viewing living cells; up to 1,500x
Scanning electron microscope
sweeps beam of electrons over specimen causing other electrons to be emitted; realistic 3-D image; 200,000x
first to look through a compound microscope
Antonie van Leeuwenhoek
made simple microscope with glass bead
saw box like things in cork called them cells
said that all plants are made of cells
said all animal cells are made of cells
said all cells come from a cell that existed before
the virus attaches to a specific host cell