Compare the structure of electron and light microscopes. What plays the role of a light beam in an electron microscope?

Compare the structure of electron and light microscopes. What plays the role of a light beam in an electron microscope? What part of the light microscope do the projection lenses of the electron microscope correspond to? What are the advantages of an electron microscope compared to a light microscope?

Parameter Electron microscope Light

microscope

Radiation source the electrons shine
Wavelength 0.005 nm 400-700 nm
Maximum useful increase x2500 x1500
Maximum resolution 0.2 nm 200 nm
Lenses electromagnets glass
An object not lively, dehydrated, small or thin living or nonliving
Dyes contain non-ferrous metals that reflect electrons colored

– As a source of electrons to create an electron beam that replaces the light beam, there is a three – electrode gun consisting of a cathode, a control electrode and an anode,

– In an electron microscope, instead of optical projection lenses (eyepiece), an optical condenser, a light microscope lens, special electrostatic or electromagnetic projection lenses are used.

– The benefits of electron microscopy;

– The high resolution of the electron microscope allows you to observe objects whose dimensions are beyond the resolution of the light microscope. Therefore, EM is used to study the ultrastructures of microorganisms and macromolecular structures; – the combination of EM with other methods allows electronic radioautographic, electronic histochemical, electronic immunological studies. EM has been widely used in morphology, microbiology, virology, immunology, genetics, biochemistry, oncology.

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