Electron microscopes

Definition

Electron microscopes use beams of electrons to achieve much higher magnifications and resolutions than light microscopes. They are essential for visualizing the detailed structure of cells and their organelles.

5 Must Know Facts For Your Next Test

1. There are two main types of electron microscopes: Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM).
2. Transmission Electron Microscopes (TEM) can magnify specimens up to 2 million times, allowing for detailed views of internal cell structures.
3. Scanning Electron Microscopes (SEM) provide three-dimensional images by scanning the surface with a focused beam of electrons.
4. Electron microscopes require specimens to be in a vacuum and often need them to be thinly sliced or coated with metals.
5. They are crucial tools in cell biology for studying ultrastructures like ribosomes, mitochondria, and the cytoskeleton.

Review Questions

• What is the main difference between TEM and SEM?
• Why do electron microscopes require specimens to be in a vacuum?
• What kinds of cellular structures can be visualized using electron microscopes that cannot be seen with light microscopes?

Related terms

Light Microscope: Uses visible light to magnify objects up to about 1000 times, suitable for viewing live cells.

Magnification: The process of enlarging the appearance of an object using optical instruments.

Resolution: The ability of a microscope to distinguish two close objects as separate entities.