How does the relationship between salt concentration effect osmosis in the aquatic plant Elodea?
From observing the cells under a microscope, we see that they are continuously moving and therefore are alive. We have observed that when the cells are in the 10% sodium chloride, the chloroplasts are positioned to the sides of the cell wall and the cytoplasm is more expanded. Cells in the distilled water are slightly smaller than the cells in the sodium chloride solution and the chloroplasts have begun moving to the same. Finally, cells in the isotonic water are very small and equally spread out through out the cells.
From observing the Elodea in different concentration of water, we can see that the more concentrated the solution is, the more osmosis occurs. This can be seen from the change from observing the plant in isotonic water, distilled water and a 10% sodium chloride solution. As the concentration of the solution increases, the cytoplasm and chloroplast was pushed to the edges of the cell membrane instead of being spread out like in the isotonic water. This observation is especially visible for the 10% sodium chloride solution; where all of its chloroplast was on the boundary and pressure of the cytoplasm is more. This occurs because of osmosis where water molecules move in the sodium chloride solution as osmosis works from a region of lower solute concentration to a region of higher solute concentration across a partially permeable membrane. The sodium chloride molecules moves across the membrane so the net is in equilibrium, due to this the elodea contain more water and therefore becomes larger. At some cells, we can see that they look very weak and full, these are the cells which are reaching the maximum capacity of water they can obtain. If we were to leave the elodea in higher concentration solution they may burst due too much water flowing and pressure inside the cells. There was only a gradual change...
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