January 31, 2007

January 31, 2007 - January 31, 2007 Cells: The Basic Units...

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January 31, 2007 Cells: The Basic Units of Life Cells: The basic unit of life The lowest structural level in which all life's properties occur Robert Hooke named cells  in 1665 Unicellular organisms Bacteria, amoeba, paramecium Multicellular organisms Animals, plants, and fungi   The Cell Theory Cells are the fundamental unit of life All organisms are composed of cells All cells come from preexisting cells   Cell Size Cell size is dependent on the surface area to volume ratio Volume -  chemical activity Surface Area -  substances entering and exiting the cell Large organisms consist of many small cells   Microscopes are used to see cells Most cells are too small to see with the naked eye Resolution is the distance apart 2 objects must be in order for them to be distinguished as  separate Human eye = 0.2mm Microscopes are used to improve resolution   Types of Microscopes Light Microscope Uses visible light and glass lenses to magnify an object Resolving power is 1,000X that of the human eye   Electron microscope Uses magnets to focus am electron beam Resolving power is 400,000 times that of the human eye
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January 31, 2007 - January 31, 2007 Cells: The Basic Units...

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