BIOL 111 Chapter Notes - Chapter 3: Stereo Microscope, Photographic Film, Computer Monitor
Document Summary
Uses an electron beam passed through magnetic lenses and is ultimately projected onto photographic film or a computer monitor for viewing: using electrons instead of visible light decreases wavelength, thus dramatically increasing resolution. Contrast: the differential absorption of light by different parts of the object being viewed: not useful for observing larger objects. Magnifications total magnification = objective lens magnification x ocular lens magnification. Cell theory: all cells come from pre-existing cells, all cells have dna as genetic material. Cytology: the study of cellular structure and function. No nucleus, just one ring of double- stranded dna. Using a scanning microscope to examine a sample of the elodea aquatic plant: easily recognizable for their rigid cell walls and green chloroplasts. Using a scanning microscope to examine a sample of onion cells: had noticeable membrane-bound nucleus. Using a scanning microscope to examine a sample of human cheek cells: different distribution of cells on the slide; scattered and not in rows.
