Cell Discovery and Theory

History of the Cell Theory  In 1665, Robert Hooke invented the first simple microscope.  He looked at a cork (dead cells of oak bark) and noticed tiny boxed shaped structures.  He named these cells.  Cell: The basic structural and functional unit of all living organisms.

History cont.  Anton van Leeuwenhoek designed another microscope. He saw small living things in water, milk, and other substances.

Cell Theory  After the discovery of the cell, many scientists summarized what they found as the “cell theory”. Cell Theory: includes three principals  Living things are composed of one or more cells  Cells are the basic unit of structure and organization of all living things  Cells arise only from previously existing cells.

Microscope Technology  Since the invention of the Microscope, advances have been made that increase the magnification and resolution. Compound Light Microscope Electron Microscope

Compound Microscope  Use light to produce a magnified image  The maximum magnification of a compound microscope is around 1000 times.

Electron Microscope  1940’s: Developed electron microscope.  Uses magnets to aim a beam of electrons at an object. Called Transmission electron microscope (TEM)  Magnified 500,000 times.  Scanning electron Microscope (SEM), gets three-dimensional image.