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The determination of the water potential of potato cells

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Introduction

The determination of the water potential of potato cells Results table Sucrose (1%) Initial mass of discs(g) Final mass of discs(g) Change in mass(g) Change in mass(1%) 0.0/distilled water 1.82 2.13 0.31 17.8 0.1 1.77 1.84 0.07 3.9 0.2 1.76 1.83 0.07 3.9 0.3 1.86 1.71 -0.15 -8 0.4 1.73 1.47 -0.26 -15 0.5 1.88 1.35 -0.49 -26 Trends and Patterns There is negative correlation on the graph so water is moving from high concentration to low. The negative correlation also shows that as you increase the number of moles of sucrose less osmosis is taking place as there is a less water molecules in the sucrose (and there is more in potato itself). Therefore the potato cells are absorbing less water (and losing more than it takes in as the net flow is going out of the cell). This shows that the number of moles of sucrose as they increase there water potential is going down until the water potential of the potato cells becomes greater than that of the sucrose so the cell ...read more.

Middle

of water inside the potato than in the solutions, therefore the water diffused out of the potatoes by osmosis because now the sucrose solution has a lower water potential, down the concentration gradient and into the solutions outside, this resulted in the loss of mass. So as the molarity increases, the potato chip suffers from more mass loss (becomes plasmolysed). And as molarity decreases, the potato chip gains mass (becomes turgid). This shows that osmosis is proportional, net movement of water only occurs when there isn't equilibrium. This process is proven in the scientific knowledge. As water molecules diffuse into the potato chip, more pressure is applied to its cell wall, this adds to water potential, as the pressure potential is increased the cells become turgid. Another important fact is that the graph makes a curved shape (if a line of best fit is drawn) that will result in the potato not being able to take in any more water. ...read more.

Conclusion

that could measure to 0.01g * Blade- the blade didn't promise concordant discs of potatoes because you were not able to accurately cut it and then the surface area, length, width were not exactly the same for each disc. Anomalies:- I have one known anomaly which is result 4 (0.3 molar solution) because it was the same as it had a very high value compared to other results (and because it was identical to the last result taken). I believe that the anomaly was due to human error which was dude to my colleague for not removing the oil efficiently or it could also be that my colleague wasn't able to cut the potato discs inaccurately giving them a bigger surface area. Improvements:- * A better weighing scale is needed one that measures to a greater degree of accuracy e.g. a weighing scale that measures to 0.001 grams * Abetter blade or slicer/cutter will help give the experiment a more accurate surface area, length, width etc which will improve the results significantly. * A more efficient method for removing the oil as this will also improve the results. ...read more.

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