BIO 327 Chapter Notes - Chapter 4: Transmission Electron Microscopy, Scanning Electron Microscope, Fluorescence Microscope
Document Summary
Light microscope- allows us to magnify up to 1000x. Bright light must be focused on the specimen by lenses. Specimen must allow light to pass through it. The lenses must be arranged to focus the image. Fluorescence microscopy- detects fluorescent dyes that stain the cells. Fluorescent dyes absorb light at one wavelength and emit it at a longer wavelength. Confocal microscopy- type of fluorescence microscope that builds the image by scanning with a laser beam. This generates a sharp image of the plane of focus-- optical section. A series of optical sections at different depths creates a 3d image. Transmission electron microscopy- uses a beam of electrons instead of light. Specimen is very thin and placed in a vacuum, stained with electron heavy dense metals. Scanning electron microscopy- specimen is coated in a thin film of heavy metal. A detector measures the quantity of electrons scattered or emitted at each point of the surface.
