TAKE ONE OF EACH!TAKE ONE OF EACH!

MicroscoMicroscopespes

Light MicroscopesLight Microscopes

How they work: lens (es) bend light, How they work: lens (es) bend light, magnifying and focusing the imagemagnifying and focusing the image

Simple Microscope: has one lensExample: magnifying glass

Compound Microscope: has more than one lensExample: modern microscope

Electron microscopesElectron microscopes

Use a beam of electrons to create the image. The beam of electrons is focused by a magnetic field.

Scanning Electron Microscope (SEM)-electron beam scans surface of object-gives a picture of the outside of the object-magnifies up to 1,000,000 X

Transmission Electron Microscopes (TEM)-electron beams pass through the specimen-gives a cross section view

What Did the Scientists What Did the Scientists See?See?

Robert Hooke: (1665)Robert Hooke: (1665)

saw the dried up boundaries of cork saw the dried up boundaries of cork cells and coined the term “cell”cells and coined the term “cell”

Anton van Leeuwenhoek (1670)Anton van Leeuwenhoek (1670)• built simple microscopes with built simple microscopes with

powerful lenses and excellent powerful lenses and excellent resolution resolution

• made first drawings of tiny made first drawings of tiny organisms he saw in pond water -- organisms he saw in pond water -- “animalicules”“animalicules”

What Did the Scientists What Did the Scientists See?See?

Cell TheoryCell Theory

1.1. All living things are All living things are composed of cells.composed of cells.

2.2. Cells are the Cells are the basic unit of basic unit of structure and function. structure and function.

3.3. All cells come from All cells come from preexisting cells.preexisting cells.