Rate of Diffusion of Mythelin Blue in Agar Jelly

3. Does the rate of diffusion change over time? How might this affect your calculated diffusion

Cells and molecules in the environment are constantly moving and changing, for cells to function properly there is a need for equilibrium to be met. The size of the cell and the solution outside of the cell affects the rate of diffusion and osmosis in the cell. Cells are constantly trying to reach an equilibrium with the molecules and substances around it, which is why there are such terms as: hypertonic, hypotonic and isotonic. The procedures allowed testing of whether or not surface area or volume increased diffusion and how different substance control diffusion. Cells are constantly moving to reach equilibrium through diffusion and osmosis.

The purpose of this lab investigation is to make 1 L of Pirate Purple dye solution. The claim states that the use of the concentration and absorbance of the Blue 1 dye and Red 3 dye will lead to the concentrations of the red and blue dye to yield 1 L of Pirate Purple dye. In order to understand molarity or concentration, familiarity with the terms of solute, solvent, and solution are very important. A Solute is a substance that is being dissolved by a solvent. A solvent is a substance that is dissolving the solute. Solution is a solute of a homogenous mixture that is dissolved in a solvent. With that being said, molarity is the moles of a solute divided by the liters of a solution (mol/L). In accordance to concentration, absorbance is used

The experiment of the lab was to demonstrate knowledge of the concepts of diffusion and osmosis. Diffusion is the movement of substances moving from a high concentration to a low concentration. For this lab the rate of osmosis was measured in concentration. The concentration stayed the same and increased through the experiment. At the beginning of the experiment the sacs were weighed to determine the tonicity of water throughout the experiment. Timing was also a factor each 15, 30, 45 minute interval the sacs were weighed and recorded. Each sac had a different amount of solution in them. The tonicity of the sacs was determined as well by the final weights and the final percent of gain or loss of water in the sacs.

Two variables that affect the rate of diffusion are the MWCO membrane and the solute concentration. Increasing the membrane size and solute concentration will also increase the average diffusion rate. Decreasing the membrane size and solute concentration will reduce diffusion rates and can even prevent all diffusion.

In performing the proper experimentation, we poured some of the methylene blue substrate in a piece of paper, for ease transport towards the agar plates. We performed it cautiously by not inhaling it, for it is a form of powder. We carefully place the substrate at the center of the agar plates, to ensure that is that there is enough space for diffusion to take place. After the moment we placed the substrate, we carefully placed a transparent ruler under the plate to measure the diameter of the substrate in 0 minutes. We carefully note the time, having a 15-minute interval and record the changes in the diameter of the substrate. We continued it, until we have an hour observation.

1) The relationship between the rate of diffusion, volume and surface area is that the surface area of a subject somewhat correlates with the volume of the object. When the surface area and volume are set up as a ratio, this gives a good idea as to how fast the rate of diffusion will be. The higher surface area to volume ratio, the faster the rate of diffusion. This is because then there is more surfaces to diffuse through and there materials to diffuse, the rate of diffusion is a lot faster. Conversely, when there is a smaller surface area for more molecules to diffuse through, the rate of diffusion will be lower.

The difference is that along with large molecules, living cells prevent molecules with positive charges and solubility. This is not representing in dialysis tubing, and is only found in living cells because the tubing is only based on molecular size (98). When referring the rate of diffusion, the concentration gradient influences the diffusion rate, based on the factors of temperature. The ability for molecules diffuse from high to low concentrations primarily depends on the concentration gradient between the two areas.(96-99). My hypothesis for the study is that in the hypotonic, hypertonic, and isotonic solutions, the direction and rate of osmosis will determine based on the concentration inside the dialysis tubing. My prediction is that if the solution is hypotonic the results will decrease, if the solution is hypertonic the results will increase and if the solution is isotonic the solution will vary and or remain constant.

The following hypothesis was made in regard to effect of the concentration gradient on the rate of diffusion: The higher the concentration gradient, the faster the rate of diffusion.

Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction?

In order to assimilate diffusion through a permeable membrane potassium permanganate and methylene blue were used in experiment. The objective was to compare the rates at which the liquid compound of different molecular weight diffused through agar. This was achieved by obtaining agar in a petri dish with two wells to hold the liquid compounds. The rate was measured by time and diameter distance diffused. This process was observed for 60 minutes at 15 minute intervals.

When the volume is too large relative to the surface area of the cell, diffusion cannot occur at sufficiently high rates to ensure this. Therefore cells size is wanted to be relatively small. Box A's surface area to volume ratio is the smallest and therefore will be very sufficient for diffusion to occur at a high rate. Box B's surface area to volume ratio is in between Box A and Box C and so therefore will not be very sufficient but diffusion can still occur at a medium

Diffusion is the transfer of molecules from an area that has a higher concentration to an area that has a lower concentration. Osmosis is the diffusion of water. The purpose of this experiment was to study the process of osmosis. In order to test osmosis, eggs that had been soaking in vinegar were taken and placed in four beakers of solution with different levels of glucose. Using this experiment we were able to determine the rate of osmosis of different solutions, with various amounts of glucose, through eggs. In the results of this lab it was found that the eggs were either hypertonic or hypotonic and that the

Diffusion is the spontaneous movement of particles from where they are more concentrated to where they are less concentrated. For this experiment, a 14 cm glass was filled with cold tap water. A drop of red food coloring was dropped in the cup. A stopwatch was used to measure the time it took for the food coloring to get to the bottom of the cup. The average diffusion rate was .78 cm a second. If a different color was used, I do not think it would have made a difference in the results. The mood of the person experimenting could possibly alter the results. For example, if a person is under stress, they may accidentally squeeze too much altering the rate of diffusion. If the water was warmer, this may have sped the

The next experiment was to test diffusion in agar solution. A petri dish with a layer of solidified agar had four holes punched in it using a No. 5 cork borer. Three holes were punched in a triangle shape with the fourth hole directly in the middle. There should be 15 mm between each outside hole and the middle hole. The three outside holes were filled with one drop each of potassium bromide, potassium Terri cyanide, and sodium chloride. The middle hole was filled with a drop of silver nitrate. It is very important to make sure that none of the holes overflow. After each has been filled allow to sit for an hour and observe the results.