Osmosis Rates in Artificial Cells
Daniel George
Department of Biology
Grand Valley State University
1 Campus Drive
Allendale, MI 49401 georged@mail.gvsu.edu Abstract The lab for this paper was conducted for the topic of osmosis, the movement of water from high to low concentration. Five artificial cells were created, each being filled with different concentrated solutions of sucrose. These artificial cells were placed in hypertonic, hypotonic, or isotonic solutions for a period of 90 min. Over time, the rate of osmosis was measured by calculating the weight of each artificial cell on given intervals (every 10 minutes). The resulting weights were recorded and the data was graphed. We then could draw conclusions on the lab.
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The dialysis tubing will be clamped at one end in order to fill it and then clamped at the other end to seal the filled bag. If the bag is not soft and floppy, the experiment will not work. Blot a bag with a paper towel to absorb the moisture and weigh it, if this blotting process is not done it could interfere with the weight readings creating inaccurate information. After the bags of the solutions are prepared, they will be placed into five different beakers with different solutions. Beakers 1-4 will be filled with tap water and the fifth beaker is filled with 40% sucrose and water. Fill each beaker with just enough water or solution so that the bag is covered and place the bags in the beakers simultaneously and record each time. Every 10 min the bags are to be taken out, blotted, and weighed again before returning them back into their respective beaker for another 10 min. The process is repeated until you have reached 90 min. The weights should be recorded in grams (g).
Results
Table 1 shows the contents of the bags and the content of the concentration it was submersed in. Bags 2-4 each contain a solution of both sucrose and water. These bags were each put into beakers containing hypertonic solution. These bags gained weight over time because the water moved from its high concentration inside the beaker to the low concentration inside the membrane of the artificial cell, the membrane being the bags that consisted of dialysis tubing. The
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.
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 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
The purpose of this lab was to observe the osmosis rates and mass changes of dialysis tubes. To this three-dialysis tubes with differing sucrose levels were tested on their rate of osmosis and weighed at 15-minute intervals. The results found described that as the sucrose level increases the rate of osmosis increased as well.
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 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
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.
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.
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.
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 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.
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
Aim The aim of this experiment is to investigate the effects of different concentrations of sugar solutions on the rate of osmosis in plant cells.
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.
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.