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Explain how the electron microscope has affected our knowledge of cell form and structure
Member rating: No Rating | Words: | Submitted: Wed Aug 06 2003
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Wednesday 9th October 2002. Explain how the electron microscope has affected our knowledge of cell form and structure. Electron microscopes use a beam of electrons instead of light to produce images of specimens. There are two types of electron microscope: - Transmission electron microscope Scanning electron microscope How an electron microscope works. Electrons are generated in an electron gun, which applies a high voltage of about 100,000 volts through a filament called a tungsten filament. The filament is heated to above 3000 degrees Kelvin, which is roughly 3273 degrees Celsius. Applying an increasing negative voltage to a cathode assembly, which is located just above an anode plate, accelerates the electrons. The anode plate has a tiny hole in its centre, the electron beam is sent through this hole creating a very concentrated beam of electrons. This beam is focused using magnetic coils that act like the condenser lenses that you find on a light microscope. The specimen is...
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