BIO 1140 Study Guide - Midterm Guide: Lipid Bilayer, Fluid Mosaic Model, Cell Junction

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Bright field light passes directly through the specimen. Dark field light illuminates specimen at an angle. Phase-contrast: diff in refraction caused by variations in density of specimen are visualized as diff in contrast. Nomarski (diff interference contrast: similar to phase-contrast, 3d appearance. Confocal laser scanning laser scan across fluorescently stained specimen, computer focuses light to show single angle through cell. Transmission (tem: bean of electrons focused on thin section of specimen in a vacuum, electrons that pass through form image, structures that scatter electrons appear dark. Scanning (sem: beam of electrons scanned across whole cell or organism, electrons excited on specimen surface are converted to 3d image. Region of tight connection b/w membranes of adjacent cells. Seal spaces b/w cells in layers that cover internal organs & outer surface of body or layers that line internal cavities & ducts (stomach, intestine & bladder keep contents from leaking into surrounding tissues)