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# How does the concentration of glucose mass affect the mass of potato sticks?

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Introduction

How does the concentration of glucose mass affect the mass of potato sticks? Planning For this investigation, I am going to investigate the process of osmosis. Osmosis is the net transfer of water, through a semi permeable membrane, from an area of high concentration to an area of low concentration. This continues until a point of equilibrium is reached, when equal amounts of water are coming in and out of the membrane, reaching a point of stalemate. This is a dynamic situation. I am going to investigate this reaction using potato sticks, which are left in a solution of glucose, to test whether the rate of osmosis changes with different concentrations of glucose, and to record the changes in mass of the potato sticks. The factor that I will be changing is the amount of glucose (g) present in the water solution. Prediction In this experiment, I predict that the potato stick will decrease in mass when there is a higher concentration of glucose present. I predict this because when there is a higher concentration of glucose than the water surrounding it, osmosis will take place in the potato, causing the mass to decrease until it becomes flaccid. This is when the potato stick looks shrunken and soft in appearance, and no more water can be drawn out. I predict this because when the concentration of glucose is higher than water in the solution, osmosis will occur. This is because water is moving the water molecules are moving from an area of high concentration to low concentration in the potato stick, and water will be lost through the partially permeable cell membrane in the potato, and the water will be diffused into the solution of glucose. Therefore, the contents of the cell have shrunk and pulled away from the cell way, becoming plasmolysed. This is when no more water can be extracted through a cell through osmosis. ...read more.

Middle

Analysis and Conclusion For my investigation to be a complete success, I needed to collect together my final results for the experiment, and then show this information in two graphs to see what patterns would emerge. This will also help me when evaluating my investigation, as it clearly shows the patterns of my results. On the line graph that I have drawn, there are several patterns that emerge from it. The graph plots the percentage difference that I worked out from the initial mass and final mass of the potato stick, against the varying concentrations of glucose that I added. The graph begins as a gently sloping gradient, and shows that the lower the amount of glucose that is added, the greater the positive percentage difference. On the more important graph though, I have graphed the final masses of the potato sticks against the varying concentrations of glucose. The graph shows that the mass of the potato sticks decreases with the greater concentration of glucose. The graph sharply drops from 0g to around 6g, but then begins to straighten out, and shows little change from around 6g to where I finished obtaining evidence, at 15g. The graphs I have done clearly show that that the further that the graph continues, the range in results is much smaller. The graphs show that when the amount of glucose present is increasing, the mass of the potato sticks is decreasing. This proves that when a greater concentration of glucose that is added to the solution, the mass of the potato stick decreases. This much is clear on the graphs that I have produced, as there is a negative slope showing, which makes me come to this conclusion. There is a scientific explanation as to why I have come to these results. The mass of the potato sticks is decreasing when a higher concentration of glucose is added because osmosis is taking place between the cells. ...read more.

Conclusion

I'm confident that if I had met all of these criteria, my overall results would be extremely close to perfect. I am reasonably confident that I have obtained enough evidence to support my overall conclusion. I believe that a set of ten results is enough, and that if I had done another set of experiments, this would have served little purpose other than to clarify what had already been confirmed. However, I could possibly have done another set of experiments, where I double the concentrations of glucose in the solution, or double the amount of water in the test tubes. This would clarify my initial results, and hopefully the final outcome of a new experiment of this nature would reflect the results I had obtained in this one. Other than that, I am pleased with the amount of evidence I have gathered throughout this investigation. I would not make a great deal of changes to my original method, although I would probably make some slight alterations to ensure that I could provide the best possible outcome. I believe it would probably have been best of me to use small beakers instead of test tubes in this experiment. It would have been less clumsy, and would probably have helped me in the obtaining of evidence. I would also perhaps use a slightly large volume of water, as 25ml seemed a slightly small amount to be using, for the size of potato sticks that I was entering into them. Other than that, I am pleased that the original method that I had set out is correct, and I followed it completely. It enabled me to acquire a good final set of results, and to set out the investigation in such a way that I find difficult to fault. Overall, during my evaluation, I have concluded that although there were some improvements I would make to the layout of my experiment, I am fairly confident that I completed it successfully, and enabled me to come to a final conclusion on osmosis in potato cells. ?? ?? ?? ?? 1 Dominic Smith 11E ...read more.

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1. ## Osmosis is defined as 'the movement of water molecules from an area of high ...

a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through.

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rate of the reaction will be faster as there is going to be more frequent collisions per second. Changing the concentration in liquids (changing pressure in gases) can also affect the rate of reaction. Concentration means that there are more particles of reactants knocking about between the water molecules and

1. ## How does the concentration of glucose mass affect the mass of potato sticks?

They will become turgid due to the osmosis procedure (movement of high concentration to a low concentration). The water is moving mainly from the water solution into the potato stick, which has low concentration. This will force the cells to increase their cell walls due to the extra fluid making

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