I. Title: The Water Potential of Potato Cells.
II. Purpose:
The purpose of this experiment was to investigate the effect of the change in concentration of sucrose on the rate of osmosis in cylinders of potatoes.
This would happen by using similar sizes and lengths of potato cylinders and applying the into different concentrations of sucrose (0,10%,30%, 50%, 70%) in foam cups then measuring the change in mass of the potato cylinders afterwards. Maintaining all variables unchanged such as pH, same size, covered solutions, and a constant temperature. The time taken for all potato cylinders will be 24 hours.
III. Introduction:
In animal cells, the movement of water into and out of the cell is influenced by the relative concentration of solute
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Lastly, type of tissue was controlled by using only one type of tissue which is the same potato.
The hypothesis is that when cells are put in a solution with a different water potential than inside of them, cells will gain or lose water. If concentration of solution is the same, there will be no change in mass.
IV. Procedure
Materials-
5 Foam cups.
5 labels
A potato
Cork borer
5 solutions
Plastic wrap
Weighing scale
Paper towels
Plastic knife
Procedures stated-
1. 5 sucrose solutions were made of increasing molarity: 0.2 M, 0.4 M, 0.6 M, 0.8 M, 1.0M. 2. 50 mL of each unknown solution were poured into 5 separate cups. A slice of potato was placed into 5 equal cylinders. 3. The mass of the 5 potato cylinders were then recorded. 4. The cylinders were placed into the foam cups with solution and covered with plastic wrap. It is to be left overnight. 5. The room temperature was recorded in Celsius. 6. The cylinders are then to be removed from the cups and carefully blotted of any excess solution. 7. The mass of the potato cylinders were recorded afterwards.
V. Data and analysis
Potato (cylinder) mass unknown solution intial mass (g) final mass (g) mass difference(g) % change in mass a 2.21 1.69 -0.52 -24% b 2.2 1.36 -0.84 -38% c 2.24 2.56 0.32 14% d 2.25 1.73 -0.52 -23% e 2.15 2.13 -0.02 -1% f 2.23 1.52 -0.71 -32%
Let potatoes in the solution set for 24 hours. When 24 hours have
Discussion: Cells need waterthis cell was hypertonic, meaning the solution had more solute; these cells were hypotonic, meaning the solutions had less solute; these cells were isotonic, meaning the solution had equal solute.
Hypothesis: I think that the potato will absorb more starch than the sweet potato and they will both absorb relatively similar amounts of water.
As the Concentration of the Sucrose Solution decreases, the more the potato’s mass increases. This is due to the solution being hypertonic. So, as the solute concentration gets lower, the potato’s water concentration will get higher, therefore more water particles from the solution will absorbed by the potato. Some changed very little in mass because the concentrations of the H2O molecules in the potato and outside the potato were equal. This equality in concentration is called Isotonic.
Water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane are equal. The diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called osmosis. The movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms. ("Diffusion And Osmosis - Difference And Comparison | Diffen"). A semi-permeable membrane known as the cell membrane surrounds the living cells of both plants and animals. Both solute concentration and membrane permeability are
Van’t Hoff’s Law suggests that the osmotic potential of a cell is proportional to the concentration of solute particles in a solution. The purpose of this experiment was to determine if there are any differences between the osmolalities, the no-weight-changes of osmolalities, and the water potentials of potato cores in different solutions of different solutes. The percent weight change of the potato cores was calculated through a “change in weight” method. The potato core’s weight was measured before and after they were put into different concentrations of a solute for 1.5 hours. In our experiment, there were no significant differences from the osmotic potentials of our results and the osmotic potentials of other scientists work. Ending with chi square values of 2.17 and 2.71, and p values of 0.256 and 0.337, concluding that there is no difference in water potentials of potato cores in different solutions of different solutes at varying concentrations.
However one beaker received 100 mL of Deionized water with a molarity of 0.0. Afterwards a cork borer was pushed through the potato and was twisted back and forth. Once the borer was filled it was removed from the potato. Pushing the potato cylinder out of the borer, this this step was repeated six more times in order to get seven undamaged potato cylinders. Using a sharp razor blade, the potato cylinders were both cut to a uniform length of about 5cm, and were removed of their potato skins. The potato pieces were also cut in half to give the cells a greater surface area in which it was easier to absorb the solution. After the cylinders were weighed on a balance and the data was recorded in Table 4. Using the razor blade each potato was cut lengthwise into two long halves. Then the potato pieces were transferred to the water beaker and the time they were submerged was recorded. This step was repeated for all potato cylinders in which the pieces were placed in solutions 0.1 to 0.6 M. The potatoes were incubated for ninety minutes. At the end of the incubation period the time was recorded. Then the potato piece was removed form the first sample. Next potato pieces were weighed the and the final weight was recorded in Table 4. This procedure was repeated until all samples had been weighed and recorded in the chronological order they were initially placed in the test solution. Afterwards the table was completed by recording the
Osmosis is defined as the tendency of water to flow through a semipermeable membrane to the side with a lower solute concentration. Water potential can be explained by solutes in a solution. The more positive a number is more likely it will lose water. Therefore should water potential be negative the cell the less likely it will lose water. In using potatoes the effects of the molarity of sucrose on the turgidity of plant cells. According to Clemson University, the average molarity of a White potato is between .24 M and .31 M when submerged in a sorbitol solution. This experiment was conducted with the purpose of explaining the relationship found between the mass in plants when put into varying concentrations of sucrose solutions. Should the potatoes be placed in a solution that contains 0.2M or .4M of sucrose solution it will be hypotonic and gain mass or if placed in .6M< it will be hypertonic and lose mass instead. Controlled Variables in this lab were: Composition of plastic cups, Brand of Russet Potatoes, Brand of Sweet Potatoes and the Temperature of the room. For independent variable that caused the results recorded it was the different Sucrose concentrations (0.0M, 0.2M, 0.4M, 0.6M, 0.8M, 1M). The dependent variable was the percentage change from the initial weighs to the final. The cup with .4 molarity was the closest to an isotonic solution and was used as the control group for the lab. Water potential is the free energy per mole of water. It is
In conclusion when the molarity level was at 0 and at .2 the potatoes had gained mass so therefore they were placed in a hypotonic environments. When the molarity level was .4 and above the potatoes loss mass so therefore they were placed in hypertonic environments. So the different in concentrations does change the mass of the potatoes because they determine the osmosis environments.
Data: Effect of Solute Concentration on Osmosis in Potato Cells (for the 6 groups of our class)
Osmosis is the passive movement of water from an area of low solute concentration to an area of high solute concentration, normally across a membrane which prevents the movement of solvent. This is a process by which materials may move into, out of, or within cells. Osmosis doesn’t depend on energy provided by living organisms but is affected by the properties of the cell membrane. The rate of osmosis is dependent on such factors as temperature, pressure, molecular properties such as size and mass, and the concentration gradient. In osmosis, the relationship between a solute’s concentration outside of cell and inside of a cell is described in terms of the tonicity of the solution outside of the cell. A cell is in a hypotonic solution when the solute is more concentrated inside the cell and therefore water moves into the cell. In this solution the cell swells as water enters, this may continue until it ruptures or hemolyzes. In the reverse condition, the cell is in a hypertonic solution
As we can see in Figure’s 1.2 and 1.3, when there was no sucrose solution, the potato increased in weight. This is due to the fact that the sucrose solution was hypertonic in comparison to the potato slice. Through osmosis, the solution moved along the concentration gradient and into the potato slice making it hypotonic. When there were higher concentrations of sucrose solution, the potato decreased in weight. This is due to the fact that the potato was hypertonic in comparison to the potato. Through osmosis, sucrose from the potato moved along the concentration gradient out and into
First I gather all my materials needed for the experiment (see materials list). Second I peel and slice potatoes weigh each potato in grams. Get these slices to weigh the same in mass because if they vary to much in mass that could affect the results of the experiment. Third I place each potato in its own beaker. Fourth once the potatoes are placed in beakers I make sure to place enough solution to fully cover the potato. Each beaker should have a different amount of
Small slices of potato are placed in six concentrations of sucrose: 0.0 M, 0.1 M, 0.2 M, 0.3 M, 0.4 M, and 0.5 M. The initial mass of potato is noted before being placed in the solution. The potato remained in the solution for one hour then the potato was removed from the solution and dried off before the final mass was noted. The null hypothesis is that the solutions of different molarities of sucrose will not affect the
Effect of Sucrose Solution on Osmosis Aim: The aim of the experiment is to show how varying the concentration of sucrose solution affects osmosis by changing different molar solutions of sucrose and water and how it affects the potato. Introduction: In this investigation I will be exploring the effect of varying concentration of sucrose sugar solution on the amount of activity between the solution and the potatoes. Osmosis is the movement of water molecules across a partially permeable membrane from a high water concentration to a low water concentration.
How do different concentrations of sucrose solutions (0M, 0.2M, 0.4M, 0.6M, 0.8M, 1M) affect the mass of potato cores when in sucrose solution?