Electron microscopes (EMs) are advanced scientific instruments that utilize energetic electrons to examine fine details of objects, achieving magnification between 100 to 250,000 times that of light microscopes. There are two primary types of EMs: Transmission Electron Microscopes (TEM), which focus on the inner structure of specimens, and Scanning Electron Microscopes (SEM), which visualize surfaces, each offering unique applications and advantages in the study of cellular and structural features. TEM enables molecular-level insights into cells and viruses, while SEM provides detailed 3D images of surfaces for various microscopic specimens.

1. ELECTRON MICROSCOPY
Bhalerao Sainath
Sub. T.- Tiwari S.

2. WHAT ARE ELECTRON MICROSCOPES ?
• Electron microscope are scientific instruments that use highly
energetic electron to examine objects on a very fine scale as,
• Topography ( Surface features)
• Morphology ( Size and Shape )
• Crystallographic Information (arrangements of atoms)

3. INVENTION OF EMs
• To study objects of < 0.2 micro meter
• For analysis of sub cellular structure
• Study of cell organelles
• Cell metabolism
• An Ems can magnify structure from 100-250000 Times than light
microscope.

4. TYPES OF ELECTION MICROSCOPE
• There are two types of Ems,
• Transmission Electron Microscope (TEM) – Allows one to study inner structure
of objects
• Scanning Electron Microscope (SEM) – Used for visualise the surface of
objects

5. TRANSMISSION ELECTRON MICROSCOPE
• TEM was discovered by Max Knoll and Ernst Ruska in 1931.
• TEM is a Microscopy technique where a beam of electrons is transmitted
through an ultra thin specimen.
• An image is formed from the interaction of the electrons transmitted through
vthe specimen
• TEM provides morphological and crystalline info. The images allows
researchers to view specimen on a molecular level by making it possible to
analyse structure and texture.

6. APPLICATIONS OF TEM
• Ideal tool for the study of ultra structure of cells
• Plant Cell

7. • Used in identification of plant and animal viruses

8. ADVANTAGES OF TEM
• TEM offer the most powerful magnification, potentially over 1 million
times or more
• TEMs provides information on element and compound structure
• Images are high quality and detailed
• They are easy to operate with proper training

9. SCANNING ELECTRON MICROSCOPE ( SEM )
• SEM electron microscope is an improved model of an electron
microscope
• SEM is used for the study three dimensional
image of the specimen
• SEM produces images of a specimen by
scanning the surface with focused beam of
electrons
• SEM gives 3D structure of objects

10. APPLICATION OF SEM
• SEM is very useful to view the surface structure of microscopic
specimen like bacteria, diatoms, pollen grains and others
.
Basillus megatherium

11. • SEM is employed in the analysis of structural features of compound
eyes of insects

12. ADVANTAGES OF SEM
• Better resolution
• Work with low voltage
• Fast imaging
• Easy to operate