BI110 Chapter Notes - Chapter 2: Differential Interference Contrast Microscopy, Electron Microscope, Mitochondrial Matrix
Document Summary
2. 1 - basic features of cell structure. Cell theory: all organisms made of 1+ cells, cell is basic structural and functional unit of all living organisms, cells arise from division of pre-existing cells. Three domains of life: bacteria, archaea, eukarya. Cells are too small to be seen by naked eye; see cells and structures using microscopy: light microscopy--> use light to illuminate specimen. Bright-field light passes directly through specimen; usually insufficient contrast to be discerned; stained w/ dye to enhance contrast. Dark-field light illuminates specimen at angle , only light scattered by specimen reaches viewing lens of microscope; gives bright image of cell against black background. Differences in refraction (way light is bent) caused by variation in density of specimen are visualized as difference in contrast; otherwise invisible structures are visible using this technique. Nomarski (differential interference contrast) similar to phase-contrast microscopy, special lenses enhance differences in density; gives cell 3d appearance.
