DIFFUSION AND OSMOSIS: WHAT’S TO EXPECT?
Diffusion and osmosis are very important in biological process. Diffusion is the movement of molecules or ions from a region of their high concentration to a region of their low concentration. Osmosis is the diffusion of water molecules across a semipermeable membrane. To gain a better understanding of diffusion and osmosis, we examine multiple experiments to show diffusion and osmosis in animal cell, plant cell and synthetic cell. In our first experiment, we weight a decalcified chicken egg and place 10% NaCl concentration. At every fifteen minutes intervals, we weight the egg and record that the weight decreases. In our second experiment, we use three slices of aquatic plant Elodea and add pond water one leaf, distilled water for the second and 20% NaCl for the third, then observe the cells of each leaf with a compound microscope. Under microscope, chloroplasts (green organelles) in Elodea tend to bound to the cell wall in pond water, spread all over the cell in distilled water, pull away from cell wall in 20% NaCl. In our last experiment, we use a dialysis bag that contains 30% glucose and starch solution then place into a beaker of water and iodine solution. We then remove the bag out of the beaker, and use two test tube which label BAG, BEAKER to perform a Benedict’s test. We place solution in the bag in the BAG tube, and solution in the beaker in the BEAKER tube and add a drop of Benedict’s reagent to each tube, then heat each test tube and observe a color change in each tube. These experiments show that movement of water of chicken egg cell and Elodea cell is “osmosis” and movement of molecules in dialysis bag and beaker is “diffusion”.
Diffusion is involved in many biological processes occurring in single-celled to complex organism (cite this). It is a part in life that we need to know and understand how it works. Diffusion is the process by which molecules move from an area of high...
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