Osmosis Lab Report Essay

4. Does the dialysis bag or the beaker contain more starch? What about glucose? The dialysis bag does contain more of the glucose and starch than the beaker does.

1. Cut four 6-inch pieces of dialysis tubing and soak in a coffee cup filled with tap water for 2 hours prior to your start

The Osmosis and Diffusion lab was conducted to provide us with information on how built up mucus affects those conflicted by the recessive genetic disease, Cystic Fibrosis., due to a mutation to the membrane regulating chloride (Cl-). This mutation prevents the Cl- from leaving the cell causing the amount of sodium (Na+) in epithelial cells, which results in extreme mucus on the lungs and airways causing this disease to be fatal if not treated but treatment does not equate to a long lifetime. During the lab we took the data from three parts: Diffusion, Osmosis in an Elodea Cell, and finally the Role of Osmosis in Cystic Fibrosis. During Part 1 we looked at diffusion across a semipermeable membrane for starch and glucose, which resulted in both having a negative solution when placed in a semipermeable membrane. Then we looked at osmosis in the Elodea Cell to watch for the occurrence of Plasmolysis, when a cell’s plasma membrane pulls away from the cell, and how a plant cell is affected by both hypertonic and hypotonic solutions. Finally, we observed the role of Osmosis in Cystic Fibrosis using dialysis bags to represent a normal cell and a Cystic Fibrosis cell with the normal containing 1% NaCl while the Cystic Fibrosis bag contained 10% NaCl. After we ran the experiment, we looked at the Percent Change in Mass and compared them after 30 minutes. We found that Cystic Fibrosis cells didn’t change mass as much as the normal cell ending with a change in mass over -1%. The

Using the graduated cylinder, measure 20mLs of the stock sucrose solution and 180mL of water to create a 3% sucrose solution and place it into the 250mL beaker (beaker #2). Place bags #1‐3 (red, blue, yellow) into beaker 2 and bag #4 (green) into beaker 1. Allow the bags to sit for one hour. After allowing the bags to sit for one hour, remove them from the beakers carefully open the bags, noting that often times the tops may need to be cut as they tend to dry out. Measure the solution volumes of each dialysis bag using the empty 250 ml beaker.

The hypothesis states 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. In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Then dialysis tubing A was placed into beaker 1 with B, C, and D placed into beaker 2 for 45 minutes and weighted at 15 minute intervals. My finding in the study was that each of the four samples changed from their initial weight and for the most part accurately proved the hypothesis.

In this study we constructed we researched whether different sucrose concentrations affect the rate of osmosis. In order to do this, we constructed artificial cells out of dialysis tubing filled with 20% sucrose and 40% sucrose and weighed them every 10 minutes for 90 minutes. In doing so, we concluded that the higher the sucrose concentration, the faster the rate of osmosis.

There were several steps completed to prepare for the experiment. Three dialysis tubes were filled with approximately the same volume of distilled water and then were tied shut. The initial mass (in grams) of the tubes was taken using a triple beam scale. I then filled three 500 mL beakers with 400 mL of water each and dissolved different masses of solute (table sugar) in each beaker in order to make 5%, 10%, and 20% solutions. The beakers were labeled accordingly, and then 20 g, 40 g, and 80 g (respectively) of table sugar was weighed out using a digital scale and placed into the corresponding beakers. The sugar was stirred in using a stirring rod until all of the solute was completely dissolved.

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

If we placed a .6M sucrose solution instead of the tap water in the beaker, it would case diffusion to occur. Diffusion is the movement of particles from a high concentration to a low concentration until they reach equilibrium. If we did this with all the different molarities (.0M, .2M, .3M, .4M, .6M, .8M) in the dialysis bags, there would different tonicities. For an example, .0 M, .2M, .3M and .4

Osmosis is a special type of diffusion where water molecules move down a concentration gradient across a cell membrane. The solute (dissolved substance) concentration affects the rate of osmosis causing it either to speed the process up or slow it down. Based on this, how does different concentrations of sucrose affect the rate of osmosis? If sucrose concentration increases in the selectivity-permeable baggies, then the rate of osmosis will increase.

In the final experiment we filled a dialysis bag with starch solution and tied off both ends of the bag so that it is water tight. We then filled a separate bag with sodium chloride and submerge both dialysis bags in two beakers of distilled water. We allowed the bags to sit in the water for 10 minutes. We then put silver nitrate into the water that held the dialysis bag filled with sodium chloride and recorded any changes in the water. We then added iodine to the water that held the dialysis bag of starch and observed any changes in the water.

The idea behind this experiment is to know how does relative concentrations of solutes affect the direction of osmosis.  Osmosis is the diffusion of water through a membrane.  Apparently, for this experiment, the dialysis tube would play the role of a cell membrane since it contains small pores.  These pores would distinguish which liquids are permeable and which ones are not.  The liquids that are going to be used for this experiment includes sucrose solution and water.  My hypothesis and prediction for this experiment is that the dialysis tube that contains water in and water outside of it will not have a change in mass.  While the dialysis tube that contains water in and sucrose outside of it will eventually lose mass.  In addition, the

Then, each group of students received the necessary materials to complete the experiment. When the students received the cups, they labeled cups to distinguish between the salt solution, distilled water, and control group. After weighing the cups and finding the mass of the cucumbers, the students poured 50 ml of water in one cup, 50 ml of salt solution in the other, and left the control cup empty. Then, the students placed the cucumbers into the cups and waited 30 minutes for the results. After the 30 minutes, the students removed the cucumbers from each solution and dried the cucumbers with paper towels. The students then weighed the cucumbers again and recorded their results. Lastly, the students found the difference from the original mass of the cucumbers and recorded their results.

Abstract: In the first part of this lab, dialysis tubs were used to test if a starch and glucose solution was diffused through the tubes. For the second part of this lab, the water potential of potato cells was determined. The purpose of this lab was to identify whether or not there was a net movement of water by diffusion into the dialysis tube due to the higher concentration of solute (starch and glucose) inside the bag, and if there was a net movement of glucose by diffusion out of the dialysis bag due to the higher concentration of glucose inside the dialysis bag. For the second part of this experiment, the percent change in mass was calculated as the concentration of sucrose increased. This will later on help to identify whether the soution is hypertonic or hypotonic.

Osmosis is the diffusion, or dispersion of water through a selectively preamble membrane from a higher concentration to a lower contraction. Temperature, particle size of the contention gradient can affect the rate of osmosis because molecules are passed. High temperature affects inn the rate of osmosis and, it’s become faster, because molecules are passed through the permeable membrane, they would at a lower temperature membrane. This size of the molecules particles affects the rate of diffusion. Osmosis can no take a place without the diffusion. In the experiment, the water molecules can easily pass through the dialysis bag cause of the size, but a source of molecules are not able to pass through the dialysis bag cause of the size. Lastly, the gradient effect in the rate of osmosis, due to the more hypotonic and hypertonic in water. Water molecules are going from higher concentration to lower concentration to more down their gradient. During the osmosis and diffusion, the water molecules are faster. The magnitude of the concentration gradient plays the biggest role in the experiment.