Investigating the Water Potential of Potato Cells

1621 WordsDec 14, 20127 Pages
Investigating the Water Potential Of Potato Cells Aims 1. To test how water potential, in a solution, affects the movement of water in and out of a cell by osmosis Prediction I predict that by increasing the water potential around the outside of the potato cell, (i.e. so that the water potential is greater outside the cell compared to the inside of the cell e.g. 0m sucrose) that the net movement of water into the cell will increase. This is due to the water potential being greater outside the cell compared to the inside of the cell, therefore water will diffuse into the cell by a process of osmosis. The opposite however will occur when the water potential outside the cell is lower than that inside the cell (i.e. with hypotonic solutions,…show more content…
I can do this by following two steps.(1). Firstly I can work out the concentration of sucrose in the potato by reading of my graph were the %change in mass is 0, as this shows that at this point there is no net movement of water hence the two areas have equal solute potentials. (In this case the morality of the potato is 0.14m.) (2). I can then use this to work out the solute potential of the potato by using the below graph, which was made from information from data sheets, showing the solute potential at different moralities. The graph shows that as you increase the sucrose concentration of the solution surrounding a potato,(hence making the solution Hypotonic)that the net movement of water out of the cell increase. This is represented by the downwards-sloping curve of the graph and is due to the increased solute potential of the surroundings meaning that there is more solute in the solution; hence more solutes form bonds with water molecules meaning that the water molecules are no longer free to move or they move more slowly. As a result of this the water enters the solute solution faster than water leaves the solute i.e. there is a net water movement out of the cell through the (permeable) membrane . This is not true however before 0.14m concentration of solution as the solute concentration is greater in the cell and therefore water enters the cell by a process of
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