Determining the Water Potential of Potato Tubers Using Gravimetric anc Chardakov Techniques

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

Aim: To investigate how effect of Detergent Concentration (cont.) has on Membrane permeability of Beetroot cells. Hypothesis: I predict that as detergent concentration increases, the solution will become less clear, plus mass increases. The increases in mass will indicate that the water potential of the Beetroot cell is lower than that of the surrounding sucrose solution. The Beetroot discs will become flaccid and decrease in mass if the water potential of the surrounding solution is lower than the water potential inside the beetroot cell.

The concept of osmotic pressure must be understood when studying osmosis. The movement of water from a hypotonic solution through the membrane into a hypertonic solution can be prevented by applying force or pressure on the hypertonic side. The force that must be applied to prevent osmotic movement of water from hypotonic to hypertonic, measured in atmospheres, is referred to as osmotic pressure. Solutions with greater concentrations of OAS have greater osmotic pressures because greater force is required to prevent water movement into them. Distilled water has an osmotic pressure of zero.

Finally, it could also be a hypertonic solution which is when there is a higher concentration of solute in the solution than in the cell and therefore the water leaves the cell. This make the cell plasmolyzed or “shrunken”. In our experiment this means that the potato cell would

The solute potential would be -2.48. If the concentration inside the cell is .15 M, then would diffusion out of the cell and into the solution of .1 M. This is due to water potential and the tendency for water to move from areas of high water potential to low water potential.

Another potential error, which might have occurred, is the temperature fluctuation throughout the experiment. The rate of osmosis will be affected if the temperature in inconsistent, as more heat increases rate of osmosis and cooler temperature decreases rate of osmosis.

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

Procedure: Variables: Controlled- water and size of potatoes. Manipulated variables- potatoes growth based on contents of solution.

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

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.

The potato cells, took in, or gave out the water depending on the concentration of the solution it is surrounded in. The results were fine and by looking at the mass measured before the experiment, you can see that there is no reading which seems to be out of the line. As the weights before the experiment range between 2.31g and 2.46g, this tells us that the potato pieces were cut well, and I believe accurate enough. The results show that: - Osmosis actually took place in the experiment.

In animal cells, the movement of water into and out of the cell is influenced by the relative concentration of solute

The purpose of this lab is to test the effect of osmosis on cucumber slices. If a cucumber slice is placed in a hypertonic solution, then the mass of the cucumber slice will decrease. Whereas, if

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

As it can be seen in the reaction above that water is required in the process of photosynthesis, another thing which can be seen that in the reaction above is that plants need water to produce glucose. Plant gets its water from roots. The Water moves from the dirt into the plants ' roots hair. This occurs by a process called osmosis. Osmosis is the unconstrained net development of dissolvable atoms through a semi-penetrable membrane into an area of higher solute fixation, in the course that has a tendency to even up the solute fixation on the two sides. As I said above that osmosis draws