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Download Biology 120 Chapter 3 Cells
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Cells Chapter 3 Cells The Cell Theory Emerges Modern cell theory • All organisms consists of one or more cells • Each new cell arises from division of another, preexisting cell • A cell is the smallest unit with the properties of life • Each cell passes its hereditary material to its offspring All Cells Have: 1. Plasma membrane • Controls substances passing in and out of the cell 2. DNA 3. Cytoplasm • A semifluid mixture containing cell components 4. Ribosomes Prokaryotic Cell Note what it is lacking Eukaryotic Cell Fig. 5-8 (a-c), p. 83 Fig. 5-8 (d-e), p. 83 Osmosis Osmosis • The movement of water down its concentration gradient – through a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration Osmosis Tonicity Experiment 2 % sucrose 10% sucrose water Fig. 5-17a, p. 89 B Red blood cells in an isotonic solution do not change in volume. C Red blood cells in a hypertonic solution shrivel because water diffuses out of them. D Red blood cells in a hypotonic solution swell because water diffuses into them. Fig. 5-17 (b-d), p. 89 Hydrostatic Pressure in Plants Are paramecium’s surroundings hypotonic, hypertonic, or isotonic? Osmoregulation Osmoregulation Woman Dies of Water Intoxication-2007 “Hold Your Wee for a Wii Contest”
