Osmosis and Water Potential

This experiment gave a visual understanding of osmosis and diffusion. The first experiment proved that solutes would move down a concentration gradient if permeable to the selective membrane. The second experiment proved different solute concentrations affect the movement of water, depending on the solute concentration inside the cell. The purpose of this lab was to look for different solutes that can cross an artificial membrane and to observe the effect of different concentrations of sucrose on the mass of a potato cell. Results for Part One suggested that the molecular weight of albumin and starch was too large to

First, we estimated the osmolarity of potato tuber cells by measuring the change in the potato’s’ weight after they were incubated in various concentrations of sucrose solutions (0.1, 0.2, 0.3, 0.4, 0.5, 0.6 M). First, we obtained 100mL of distilled water, and 100mL of each sucrose solution-which we placed in separate 250mL beakers. We then used a cork borer to extract 7 cylinders of potato. We then cut them all to about 5 cm long, and removed the skin from the ends. We placed all seven potato samples in a covered petri dish so they would not dry out. For consistency, we assigned each person their own, separate task to perform to each potato cylinder. First, one person removed the potato cylinder from the petri dish and used a paper towel to blot. Then

After they soaked, they were dried, placed back in the Petri dishes, and individually weighed again to determine whether each slice was hypotonic or hypertonic to the NaCl solution it was placed in, based on percent weight change. When the experiment was complete, Microsoft Excel was used to further analyze the data by viewing the percent weight changes for each potato slice in the form of a Scatter Plot

If I am to figure out the estimated concentration of sucrose found naturally inside the potato using osmosis, then there will be a change in the mass of the potato because it will either be hypotonic or hypertonic to the cell, as it will affect the size of the cell along with in. The 0 M, 0.2 M, and 0.4 M solutions were are hypotonic to the cell. Hence, they contained less solute than the potato itself. Therefore, the potato cell increased in mass because water was moving into the cell. It was more concentrated had less water in comparison with outside the cell, so it moved in. However, the 0.6 M, 0.8 M, and 0.10 M solutions were hypertonic to the cell, causing the potato cell to decrease in mass as water was moving out of the cell. There was

Purpose: To determine the concentration of solute in the potato’s cytoplasm by measuring the change

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

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

The purpose of these experiments is to examine the driving force behind the movement of substances across a selective or semiperpeable plasma membrane. Experiment simulations examine substances that move passively through a semipermeable membrane, and those that require active transport. Those that move passively through the membrane will do so in these simulations by facilitated diffusion and filtration. The plasma membrane’s structure is composed in such a way that it can discriminate as to which substances can pass into the cell. This enables nutrients to enter the cell, while keeping unwanted substances out. Active

My prediction is that as the concentration increases, the potato cell will lose more weight. This is because of the osmosis of water particles from the potato cell cytoplasm to the solution, resulting in a loss of weight. As the concentration decreases, the potato will lose less weight until a certain point where the osmosis of particles in and out of the potato cells will be equal. I also predict that as the salt

The aim of this experiment was to test the effect of surface area on osmosis and the effect of solute concentration on osmosis. To test this aim to hypotheses were devised. 1) If potato pieces are immersed in various salt solutions, then the pieces with the greatest surface area to volume ratio will experience the greatest weight change, because more water can move by osmosis across the potato cell’s semi permeable membrane. 2) If potato pieces are immersed in various salt solutions, then the pieces immersed in the most concentrated solution will experience he greatest weight change,

The results supported the hypothesis that the osmotic potential of potato would be somewhere that intermediates between a dilute solution and concentrated solution. When the change in mass of the potato

An anomaly will be that when the mass of the potato was measured for 6% of sugar solution, the mass at time 5minutes was high then it decreased sharply at times 10 minutes to time 20 minutes this shows that the pressure with which the potato shrunk made the potato less rigid which made the cell membrane of the potato start shrink from the cell itself therefore causing the mass to decrease, also from 20% to 60% of sugar solution was used the mass of the potato decreased sharply as time went on which also shows that the cell membrane of the potato has plasmolysed which shows that the cell membrane has pulled away from the cell which shows with the shrinkage of the potato.

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.

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

This experiment was used to examine the hypothesis that: Osmosis is dependent on the concentrations of the substances involved.