A cell that is full of water 2525 Words 11 Pages Investigate the Osmosis of Potato Cells in Various Salt Solutions Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. After carrying out this experiment I have realised that it is very important to represent the data in a very clear, and ordered table, chart or graph so that the numerical data is easy to handle, and therefore ready to analyse and understand from a glance rather than having to spend a long time just trying to understand what figures belong to which beaker. However, for A-level studies you would need to convert the concentrations into molar equivalents, and process the data on graphs showing standard deviation bars in order to assess the variation in repeats. Conduct your experiment and include the results with your determination of which solution you had. If you look back at my results table and graph you can see my readings are fairly accurate and reliable. There is no net loss or gain of water by osmosis.
But, if I was doing this experiment on a more scientific level I would probably use about twenty different solutions and this would help my conclusions to be more precise. The scales I used calculated up to two decimal places and this showed clear differences to others results that only recorded one decimal place. Note the texture of the potato — is it turgid or flaccid or no change from the start? The feel of the chip will also be noted because this can give an indication of the turgidity of the cells. If the concentration of the sugar solution is too strong, no deplasmolysis will take place indicating death of protoplasm. Pour approximately 15-20 ml of each of the following solutions into separate bags. These all started at 6. If I had used scales to say, four significant figures, this would of course have been much more accurate and my conclusions would have been more reliable.
In the present experiment the initial osmotic pressure of the cell has been taken as its maximum osmotic pressure and at isotonic concentration of the external solution this equals the D. The bag's initial mass is 20 g, and its final mass is 18 g. You will also learn how to calculate water potential. The potato chip will be measured before it is put in the solution, and after. When they take up water by osmosis they start to swell, but the cell wall prevents them from bursting. Prediction I know from my preliminary experiment that when a potato cylinder was placed into a test tube filled with 30cm cubed of water the potato cylinder would increase in mass but the potato cylinder that was placed in 30 cm cubed of 1. · The temperature of the solutions must remain constant e.
Hypotonic means the environment has less solutes compared to the inside of the cell. This means they are less likely to get the concentrations confused in the course of the procedure. Also cutting the potato cylinders to the correct lengths, widths and masses and having to measure them with a ruler, was very time consuming and not as precise as I would have liked. We will do the activity in the solutions with concentration of 0, 0. When immersed in pure water again, the turgour pressure increases due to endosmosis and as a result the suction pressure falls.
Determine the molar concentration of the potato cores. Plant cells become turgid when they are put in dilute solutions. Results are plotted on a graph paper taking sugar concentrations as abscissa and the percentage change in weight as ordinate. Variables: To create a fair test, certain aspects of the experiment will have to be kept the same whilst one key variable is changed. Turgid means swollen and hard. Hypotheses: I hypothesis that when the potato cylinder is in the solution of distilled water it will not change size as the distilled water solution is a Isotonic solution, and as outlined in my introduction the net movement from the solution to the potato will be the same. This means there is a higher water potential inside the solution compared with the potato.
Analysis: In my experiment I predicted that when a potato cylinder was placed into a test tube filled with 30cm cubed of water the potato cylinder would increase in mass but some of the potato cylinders that were placed in 30 cm cubed of different concentrations of sucrose solution would only increase in mass by a minute amount. Experiment 3 Demonstration of Plasmolysis and Determination of Isotonic Conc. Another thing that would have caused some error in the experiment isthat the experiment required more than one piece of potato thusly 2needed to be used and that gives us 2 different sources of sucrose andeach piece of potato might have had a different amount of nutritionthusly affecting the amount of sugar in each so that might haveaffected the results of the experiments that were conducted. Then the potato pieces will be removed and dried using paper towels and then re-weighed. I will measure the mass in grams. The isotonic concentration may be determined, as in Expt.
Therefore if there is a higher concentration of sucrose molecules outside the cell then the net movement of water molecules will be out of the cell and similarly if there is a higher concentration of sucrose molecules inside the cell then the net movement of water. Aim - This experiment aims to show the movement of water molecules in and out of the potato cells when potato strips are immersed in differently concentrated solutions through osmosis. Calculate the solute potential Ψ for the sucrose solution using the formula below. Leave the potatoes for 24 hours 5. The frozen tissue is then allowed to melt.
This is the reason plant roots take in water: the rain water the enters the soil has a higher water potential than inside of the roots, so water moves into the roots by osmosis. Thus it could differ during the experiment. We planned to set up our experiment in the following way. I put 20cm3 of each concentrate into 3 different boiling tubes… 3437 Words 14 Pages Investigate the Effect of Varying Solution Concentration on Osmosis in a Potato Chip Prediction A definition of osmosis is: 'the movement of water molecules from an area of high water concentration to a low water concentration across a semi-permeable membrane' Oxforddictionary 2000. What will keep potatoes or other veggie fresher: soaking it in regular water or salt water? Osmosis is the flow of water by diffusion through a differentially permeable membrane from areas of high water concentration to regions of low water concentration. In plant cells, the presence of a cell wall prevents the cells from bursting, but pressure does eventually build up inside the cell and affects the process of osmosis. Then multiply answer by 100.
The vessel containing the experimental tissue is surrounded with a mixture of ice and common salt. We decided to do 5 different types of solutions so we would have a wide range of results and it would be more accurate. Remove the cylinders from the beakers and record the mass. Or, working groups could be allocated tasks for the whole class, for example, setting up the range of dilutions, cutting the potato chips, recording data. What about the temperature of water? In this experiment I will weigh and blot rings of potato and test them in different concentrations of sucrose solution. Simply, will the effect of the action of osmosis be affected by the concentration of the solution? After 10 minutes the tissue is taken out and osmotic pressure suction pressure or D. Our help is done step by step such that your expectations and stardards are met.
This would be the sucrose molarity in which the mass of the potato core does not change. Using black pen to label the 3 different concentrated solutions and label them A, B and C. The following equation relating to freezing point depression and osmotic pressure may be employed: O. We can demonstrate this in a lab setting using potatoes. Observation: After some time the liquid inside the pipette rises. For actual determination of A of cell sap, the cell sap at first must be extracted by killing the cells by freezing. In case of individual cells, this method of determination of isotonic conc.