ppt of lec 3 electron microscopy

this is the ppt of the lecture:
Objectives: Upon completion of this lecture, the student should be able to:
1- Explain the main components of SEM & TEM.
2- Discus the differences between light and electron microscopy.
3- Differentiate between SEM and TEM images.
4- Describe briefly how to use the Autoradiography method for macromolecules localization.
Transmission and scanning electron microscopes are based on the interaction of electrons and tissue components. The wavelength in the electron beam is much shorter than that of light, allowing a thousand-fold increase in resolution.
Transmission Electron Microscopy
The transmission electron microscope (TEM) is an imaging system that permits very high resolution (3 nm) (Figure 1a). This high resolution allows magnifications of up to 400,000 times to be viewed with details. Unfortunately, this level of magnification applies only to isolated molecules or particles. Very thin tissue sections can be observed with details at magnifications of up to about 120,000 times.