BIOLOGY AS Unit 1

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  • Created by: Sally
  • Created on: 23-11-12 18:43
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  • Unit 1: AS CELLS, EXCHANGE AND TRANSPORT
    • CELLS
      • MICROSCOPES
        • Light Microscope:
        • Electron Microscope
          • Advantages
            • Scanning Electron Microscope
              • Can produce a 3D images of the cells- which can reveal the detail of tissue arrangements.
                • The magnification possible is x100,000
                  • Resolution: 0.5 nm
                    • Works by bouncing electron beams off  the surface of an object.
                      • Can produce a 3D images of the cells- which can reveal the detail of tissue arrangements.
                        • The magnification possible is x100,000
                          • Resolution: 0.5 nm
                            • Works by bouncing electron beams off  the surface of an object.
              • Transmission Electron Microscope.
                • Resolution: 0.1 nm
                • The electron passes through a very dense prepared sample.
                  • Electrons pass through the denser parts of the sample less easily so it gives it more contrast.
                    • Transmission Electron Microscope.
                      • Resolution: 0.1 nm
                      • The electron passes through a very dense prepared sample.
                        • Electrons pass through the denser parts of the sample less easily so it gives it more contrast.
                        • Magnification: x500,000
                  • Magnification: x500,000
                • The resolution is O.1 nm (2000x more than the light microscope.)
                  • The microscope can therefore produce detailed pictures of the structures and organelles within the cell.
                    • Advantages
                      • Scanning Electron Microscope
                        • The resolution is O.1 nm (2000x more than the light microscope.)
                          • The microscope can therefore produce detailed pictures of the structures and organelles within the cell.
                  • Limitations
                    • Transmission Electron Microscope
                      • The image produced is two-dimensional 2D.
                    • Scanning Electron Microscopes
                      • Electron microscopes are very expensive.
                        • Transmission Electron Microscope
                          • The image produced is two-dimensional 2D.
                    • Untitled
                    • Preparing samples and using an electron microscope both requires a high degree of skills and traiing.
                • MAGNIFICATION
          • Scanning Electron Microscopes
            • Electron microscopes are very expensive.

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