Biology 3.2 The Electron Microscope

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  • Created by: Anna
  • Created on: 11-04-13 19:58

Electron microscope has two main advantages:

  • Electron beam has v. short wavelength, can resolve objects well.
  • Electrons are negatively charge, beam can be focused using electromagnets.
  • Some can resolve objects just 0.1nm apart

However, electrons are absorbed by molecules in the air so near-vacuum must be created.

Transmission Electron Microscope (TEM)

- Consists of electron gun that produces beam of electrons, focused onto specimen by condenser electromagnet.

- Beam passes through thin section of specimen - parts absorb electrons and appear dark, others allow electrons to pass through and appear light.

- Image produced on a screen, can be photographed to give a photomicrograph.



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