Potato Osmolarity Lab

“Essential Biology with Physiology” by Simon, Dickey, Hogan, and Reece, defines osmosis as follows: “The diffusion of water across a selectively permeable membrane is called osmosis.” An experiment was done in BIO 100 regarding osmosis. 5 different teams got together and each of them has a task. To record the weight change in potato strips that have been placed in different concentrations of salt solution after 30 minutes. The groups were to observe the change in weight. The movement of water through cells is often called osmosis. Osmosis applies to the daily life in many different ways. Osmosis assists plants in receiving water, it helps in the preservation of fruit and meat, is used in kidney dialysis, and can be reversed to remove salt and other impurities from water. Osmosis is a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. If the solution was hypertonic, more water would move out of the potato. If the solution was hypotonic, more water would move into the potato. Our group had a 0% solute concentration so our hypothesis was that it would be a hypotonic solution, and the potato would absorb the

The purpose of this experiment was to incubate potato tubers in solutions with increasing molarities of sucrose to determine osmolarity based on the weight of the potato tubers before and after incubation. After removing the potato tubers from the beakers, we weighed the pieces and recorded the weights. We then observed the weight change and percent change in weight of the potatoes. In every concentration of sucrose the weight of the potato tubers increased, with the largest change in weight being in the 0.2M solution of sucrose with a change of 9.5%. The smallest change in weight was in the 0.4M solution of sucrose; the change in weight was 0.47% (Table 1).

This effect will be measured by calculating the percent change of mass in grams of the potato tubers before and after soaking in six solutions, all with different sucrose concentrations. The original mass was divided by the change in mass, and then multiplied by 100 to get the percent change in mass. Substances, such as water and sucrose typically move from an area of high concentration to an area of lower concentration. For example, if there is a higher concentration of water outside of the cell, water will move into the cell where there is a smaller concentration of water molecules. Null hypothesis: If there is a change in the concentration of sucrose, there will be no change in the percent mass of the potatoes.

they are submerged in two saline solutions (1.0M and 0.5M) for twenty-four hours. The experiment requires six pieces of potatoes, cut into two inch rectangular pieces. It also requires an electric scale to measure the weight of the potatoes. The last thing required is two solutions that are in beakers, one must have a 1.0M saline solution, and the other must have a 0.5M saline solution. While doing the research for this project, I produced my hypothesis, I believed that if the three potatoes in the 1.0M solution were submerged all night, then they would loose more weight due to the overwhelming amount of salt in the saline solution. The water from the potato would exit, causing a notable amount of weight loss. This was my hypothesis because of the amount of water that would leave the potato when osmosis was taking place. For my hypothesis along with the experiment, I found a few websites to be crucial to my understanding of osmosis/diffusion and the process that would be taking place to the potatoes. An article that benefitted me was an article called ‘’Osmosis in Potatoes’’ by Claude E. Phillips Herbarium, this source gave important information to better my background information going into the experiment. I learned that the water in the potato moved outwards due to the high amount of salt in

2. Add 5 mL of water (0% sucrose) to the 50-mL graduated cylinder. Use the pipet to add or remove small quantities of liquid so that the water is exactly at the 5-mL mark. 3. Record the total mass of the liquid and graduated cylinder and liquid in Table 2.

Method: • Using the knife and the chopping board cut 3 pieces of potato. (4cm by 1cm) Cut 3 potato slices for each of the 5 containers • Place your potato slices in each of the containers • Mix one cup of distilled water with 1 teaspoon of salt. • Repeat for the next 4 containers, each time increasing the salt content. For example: Container 1: 1 teaspoon of salt Container 2: 2 teaspoons of salt Container 3: 3 teaspoons of salt Container 4: 4 teaspoons of salt Container 5: 5 teaspoons of salt • Add the salt solutions to each of the containers and start the timer for 1-3 hours • Leave the solution to sit until the time is up. • When the time is up remove the potatoes from the containers one by one and measure the potatoes using the ruler and then record the results for each potato.

Osmosis with Different Molar Solutions into Starchy Potatoes Introduction: Osmosis is defined according to Kevin M. Bonney as the diffusion of water cells through a semi-permeable membrane to the location where the there is a lower concentration of water molecules (2014). Osmosis is a form of passive transport, which means that it does not take any energy for these water molecules to diffuse across the membranes down the concentration gradient (Krane, 2014). The phrase “down the concentration gradient” means going from an area of high concentration to an area of low concentration (Krane, 2014).

Taylor Kapitanek Biology 200A- 005 30 September, 2014 Abstract This “Estimating Osmolarity by Change in Weight of Potato Tuber Tissue” experiment was conducted to determine the molarity of sucrose concentration where the mass of potato tuber segments does not change, indicating an isosmotic concentration. Indicating an isosmotic concentration was done by calculating the change of mass of the potato tuber cells prior to incubation against the mass after incubation in the sucrose solution. My groups goal was to determine what type of osmotic concentration was created as compared to the potato tissues.

The aim is to find the concentration (mole/dm3 (M)) of solute in a potato cell by using the process of osmosis and different concentrations of sucrose solution.

The effect of sugar solutions (%)with different concentration levels on the rate of osmosis in cylinders of potatoes(+/-0.01g)

C. Create a graph of your experimental data by plotting the percent change in potato mass against sucrose molarity. Label the x-axis as “Molarity of Sucrose,” and the y-axis as “% Change in Mass.”

Hypothesis If the amount of sugar concentration increases, then the weight of the potato cylinders will decrease. Prediction When the amount of sugar concentration is at 15%, then the weight of the potato will not change.   Raw Data table The Effect of Change in Sucrose Solutions on the Mass of the Potato Sucrose Concentration (%) Mass of Potato (grams ± 0.05 g)

Based on the experiment result, it supports my hypothesis that as the concentration of sucrose increases the mass of potato decrease due to its temper is that water particles go high concentration to low concentration. The consequence, when 4M sucrose solution has a potato, then the solution will make the potato to shrinks because water molecules from potato go to 4M sucrose solution due to osmosis and this is diffusion of water particles. In opposite way, mass of potato increased when it was put in distilled water because distilled water is higher solution of water particles than potato so the molecules from water entered into the potato. According to these, a feature of diffusion moves high to low concentration, water molecules passed to

Osmosis, the diffusion of water through a semi-permeable membrane, shows that water tends to flow from a hypoosmotic environment to a hyperosmotic environment. There are many proposed explanations for why and in what context this osmosis occurs. One explanation is a “concentration of particles” explanation called van’t Hoff’s Law. This law states that the size of a particle will not change the water potential or occurrence of osmosis in a solution-submerged cell, only the amount of the solute in the solution will affect osmosis. To test this, we used three different sized solutes—sucrose, glucose, and NaCl—to see if the size of the solute had an effect on the osmosis of water into or out of white potato cells that were submerged in solutions containing the 3 solutes. We found that the size of the particles of solute does not affect osmosis of water into or out of the potato cells, only the amount of particles present in the outside solution, thus supporting van’t Hoff’s Law.

Starting with the carrots, add the first amount of concentrated sugar solution (which is distilled water) and repeat this another 2 times.