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.