2. Visualizing+Cells

2. Visualizing+Cells - Resolving Power of Microscopes Limit...

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Resolving Power of Microscopes μm (micrometre) = 10 -6 m nm (nanometre) = 10 -9 m Å (angstrom) = 10 -10 m < 100 μm < 10 nm < 1 Å Limit of resolution – separation at which two objects can still be seen as distinct. Depends on the wavelength of the light and the numerical aperture of the lens system Light Microscopy Limitation of resolution – a given type of radiation cannot be used to probe structural detail smaller than its own wavelength. Light microscope resolution is determined by the wavelength of visible light. 0.4 μm (violet) – 0.7 μm (deep red) In practice, only objects > 0.5 μm can be resolved by light microscopes. Limitation is the practical consequence of the fact that light waves travel through an optical system by a variety of different routes – can interfere with one another to cause optical diffraction effects . Fluorescence microscopy illumination fluorescent molecule emits longer bright fluorescent source absorbs light at specific wavelength signal on black wavelength background filter allows only emitted light to pass Highly sensitive, most often used to detect specific proteins or other
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This note was uploaded on 12/16/2008 for the course BIOL 313 taught by Professor O during the Spring '08 term at McGill.

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2. Visualizing+Cells - Resolving Power of Microscopes Limit...

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