Investigating the Difference in Isotonic Point in Sweet and White Potato

by 15 C each time until I get to 80 C. I will measure the amount of

Next, I poured distilled water just below the 250ml mark on the neck of the volumetric flask.

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.

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?

Measure 500ml of tap water in the 500cm3 beaker, then measure 5g of sodium hydrogen carbonate using the 50cm3 beaker and weight scale and place in the beaker of water, using the glass rod to dissolve it into the mixture.

In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Beaker 1 is  250- mL and contained 150-mL of 10% sucrose with dialysis tubing A, while beaker 2 (a large bowl) contained 1% sucrose, with dialysis tubing  B, C, and D. Tubing A contained 10-mL with 1% sucrose. Tubing B

The graph above indicates that as the concentration of sucrose solution (%) is increased, the percentage change in mass decreases, thus it can be supposed that there is a negative correlation between the sucrose concentrations and the mass of potato cubes. It is also apparent from the graph above that an error has occurred during the 15% sucrose trial as it appears as an outlier also it can be estimated from the graph that approximately10% sucrose solution is the isotonic condition as there is no big change in mass.

Prepare standard solution #1, Take 1 ml sub stock solution from the 100 ml beaker and then put into 25 ml volumetric flask with the help of 10ml graduate pipette.

Measure and add 5cm3 of buffer solution using a measuring cylinder with the pH 3 into a test tube using a pipette and place the potato cylinders into the test tube.

3.Measure and add 0.5g, 1.0g, and 1.5g of sucrose into 3 of the test tubes. Do not add sucrose into the 4th test tube because this will be the control. Lightly shake the test tube to mix the contents together.

In order to minimize errors and to "place" the solutions in the same environment, the same volume should be extracted from each solution using the syringes.

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

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 a special type of diffusion. It is the diffusion of water across a semipermeable membrane which is a membrane that is freely permeable to water but is not freely permeable to solutes, the water moves from a dilute solution to a more concentrated solution (Karp, 2010). Both diffusion and osmosis are passive transport, energy is not used in the transport. In osmosis water moves across a membrane toward the solution of greater concentration, because the concentration of water is lower there (Martini and Bartholomew., 2007).

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.