Osmosis And Diffusion Using 6 Potato Cylinders

Diffusion is defined as the movement of molecules from an area of high concentration to an area of low concentration. The diffusion of water molecules through a semi-permeable(selectively permeable) membrane is osmosis. Semi-permeable means that some molecules can move through the membrane while others can not. Diffusion and Osmosis are passive forms of transport requiring no energy. Active Transport utilizes energy in the form of ATP. Water is a solvent that can dissolve a number of substances more than any other substance. Wherever water goes, through the ground or a body, it takes along valuable molecules. Water’s chemical composition causes it to be attracted to many different molecules and be attracted so strongly it disrupts the forces and dissolves it. Water can pass through the semipermeable membrane without any help but can change the solution, on the other side of the cell membrane, depending on how much it diffuses in and out.

The Diffusion and Osmosis Lab determines the molarities of various sucrose solutions based on change in mass. Using table sugar in different amount of molar concentration 0.0M, 0.2M, 0.4M, 0.6M, 0.8M and 1.0M. The molarity of the solution of the sucrose solution in the dialysis tubing determines the amount of water that either move into the bag or out the bag, which also means its mass changed.

The main purpose of the experiment was to test the idea that water would move from the higher concentration to the lower concentration. In order to test this theory, we placed potato slices in 7 different containers, each containing different concentrations of NaCl, to measure the weight change from osmosis. The containers ranged from 0M NaCl all the way to .6M NaCl. We measured the potato slices before and after placing the slices in the solutions and recorded the net change in weight to determine the tonicity of the potato cells. Our results showed that the potato slices put in a NaCl solution of .2M or higher lost weight and the potato slices put in a NaCl solution of .1M or lower gained weight. This shows that the osmolarity of the potato falls within the range of .1M to .2M, and it also proves the process of Osmosis by having the higher concentration move to the lower concentration. In addition to this, it can be concluded that the osmolarity of cells can be determined by observing the affects of osmosis.

Osmosis is the diffusion of water across a membrane to create an equilibrium between the levels of concentration of a solute both inside and outside the cell. In this case the solute will be sugar as the potato core will be immersed in sucrose solution.

Repeated Trials: In procedure one, we tested diffusion on different sized cell models (gelatin with various volume and surface area wise). In procedure two, we tested cell models in different internal environments and similar external environments to find the effects on rate of osmosis. In procedure three, we used potato cells in different concentrated sucrose environments to test the effects on water potential on cells and osmosis.

Osmosis is a special type of diffusion. It is the diffusion of water molecules across a semipermeable membrane (a membrane that allows for the diffusion of certain solutes and water) from an area of higher water concentration to one of lower water concentration. For example, if a 1 M aqueous starch solution is separated from a .5 M aqueous starch solution by a semi-permeable membrane, then water molecules will move from the .5 M aqueous starch solution (higher water molecule concentration) toward the more concentrated 1M starch solution (lower water molecule concentration) until an equilibrium of water molecules exists between the two solutions. Since the semi-permeable membrane did not allow for the passage of starch molecules, the 1M-starch solution will gain in volume as the water moves in (Figure 3).

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.

In conclusion, the potato cube with the highest surface area to volume ratio (the 1x1x1 cube) had the fastest rate of diffusion as it had the largest percentage increase in mass. While all the other cubes of potato had larger increases in mass at face value compared to the smallest cube, the smallest cube had the largest overall gain in percentage. The results support my hypothesis that the smallest cube will have a higher rate of osmosis because it has a proportionally larger amount of surface area compared to its volume.

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

All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help.

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.

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.

Osmosis is the movement of water molecules from high concentration to low concentration through semipermeable membranes, caused by the difference in concentrations on the two sides of a membrane (Rbowen, L.). It occurs in both animals and plants cells. In human bodies, the process of osmosis is primarily found in the kidneys, in the glomerulus. In plants, osmosis is carried out everywhere within the cells of the plant (World Book, 1997). This can be shown by an experiment with potato and glucose/salt solution. The experiment requires putting a piece (or more) of potatoes into glucose or salt solution to see the result of osmosis (a hypertonic type of solution is mostly used as it would give the most prominent visual prove of

Within every cell, a movement of a solvent occurs through a semipermeable membrane to equalize the concentration of solute on both sides of the membrane. The diffusion of water across the cell’s membrane down to its concentration gradient is called osmosis. In this case, the concentration gradient is the difference of density between one side of the cell membrane to the other. Since the cell’s membrane is permeable, particles can flow freely in and out of the cell, but the net flow will be strong in the direction of lower concentration until the system has reached a stage of equilibrium, the point at which both sides of the membrane are equal. In the