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To determine the isotonic point of plant tissue (potato).

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AS COURSEWORK To determine the isotonic point of plant tissue (potato). Introduction. This experiment is to determine the role of water potential of tissues in plants most particularly the movement of water into and out of potato storage tissue so that the isotonic point can be identified. Prediction. Potato is a plant that contains more starch grains and immature chloroplasts in the plant cells. Thus it has a lot of starch and little or no mono or disaccharides. I would predict that the when the potato chip is left in the solution it will increase in mass or decrease if the concentration of the solution is high or low. This is so because as the solute concentration increases this creates a hypertonic solution, thus more cell sap will be lost to create an osmotic balance. Also as the solute concentration decreases it creates a hypotonic solution and so less cell sap is lost but more solution is gained into the cell sap from the surrounding solution to create and maintain an osmotic balance. At a certain concentration of solute, there will be no change in mass of the potato. ...read more.


5. Temperature. The experiment will be carried out in the lab and might possibly last overnight. Because I want to keep the temperature constant a water bath will be used to ensure this. This is important because high temperature can cause molecules to have more kinetic energy and move faster thus causing osmosis to occur faster so this will cause different readings. Agovi. Measurements. I will be measuring the sugar concentrations. The concentrations will be in five (5) different concentrations (i.e.) 0, 0.2, 0.8, 1 & 5M. The readings will be replicated three (3) times with a range of at least five (5) times. This is so because it will enable me get accurate measurements. Possible methods. I can identify the isotonic point by measuring the weight, length or volume of the chips. I will measure the change in mass as its quite accurate since change in length or volume is not because the cell wall is rigid being made out of cellulose and thus will allow the cell to expand or contract to a limited extent. ...read more.


9. Calculate the change in mass per gram for each concentration and then the average change in mass per gram in order to allow accurate comparisons. You can then plot a graph of the average change in mass per gram against the sucrose concentration. Equipment. 15 watch glasses 18 cylinders of potato Agovi. Meter rule Top pan balance 50ml syringe 5 Distilled water 350cm Sucrose solution 750cm, 1M Test tubes 20 Blotting paper Scalpel Risk assessment. 1. The scalpel is so sharp so care should be taken whilst cutting the cylinders. A tile should be used and cutting must be done away from the body. 2. Pushing the potato away onto the tile, use Cork borer and the cylinder can be pushed out using a blunt object e.g. pencils. 3. All glassware should be handled carefully to ensure no breakages. Should any breakage occur, it should be cleaned and cleared away to avoid any risk of injury? 4. If any sucrose solution is spilt it should be cleaned away otherwise the area will be sticky. 5. 6. 7. 8. ?? ?? ?? ?? 1 ...read more.

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