Ch. 2.2 Viewing Cells
Magnifying Cells Cells can not be seen with just our eyes. We need something to be able to see them magnified.
Early Microscopes 1st microscope made by putting 2 magnifying glasses together in a tube.
In the 1600’s Anton van Leeuwenhoek made a microscope with glass bead lens. He could magnify up to 270 times.
Modern Microscopes A simple microscope only has one lens like a magnifying glass. Compound light microscopes has 2 sets of lenses. The eyepiece has a lens and then there are several lenses in a tube structure. All microscopes magnify, change the size, of the object.
Magnification The powers of the eyepiece and objective lens determines the total magnification. Example: The eyepiece magnification is 10X and the objective is 40X, the total magnification is 400x (10x times 40x)
Electron Microscopes Do not use light, instead use a beam of electrons. Can magnify images to greater amount than light microscopes.
Scanning electron microscopes produce a 3D image of the outside of the specimen.
Transmission electron microscopes produce a 2D image of a sliced section of a specimen.
Cell Theory With the founding of the microscope it lead to the discovery of cells. Several finding lead to the cell theory: 1. All organisms are made of one or more cells. 2. The cell is the basic unit of organization. 3. All cells come from other cells.