Osmosis and Diffusion Via Dialysis Tube

If the solution in the left beaker contained both urea and albumin, which membrane(s) could you choose to selectively remove the urea from the solution in the left beaker? How would you carry out this experiment?

In this lab experiment, half our group observed and measured osmosis using dialysis tubes that were represented as the semipermeable membrane. It is permeable to water and other small molecules but is impermeable to larger molecules such as the sucrose solution used in each of the four beakers and tubing. The other half of our group observed the tonicity of sheep blood to determine whether the blood was isotonic, hypotonic, or hypertonic. The 85 g/dL of NaCl solution was the ideal isotonic number in relation to the sheep blood cells as well as a reference to the other observations of the solutions.

Hypothesis: If we add higher concentrations of sugar to the dialysis tubing, then the net movement of coffee into the dialysis tubing will increase.

We hypothesize that as the solute concentration increases, more water will diffuse into the dialysis tubing (shown by a greater percent increase in mass).

Dialysis tubing is a membrane made of regenerated cellulose fibers formed into a flat tube. If two solutions containing dissolved substances of different molecular weights are separated by this membrane, some substances may readily pass through the pores of the membrane, but others may be excluded.

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).

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.

The objective of this experiment is to develop an understanding of the molecular basis of diffusion and osmosis and its physiological importance. Students will analyze how solute size and concentration affect diffusion across semi-permeable membranes and how these processes affect water potential. Students will also calculate water potential of plant cells.

Secondly, osmosis was to be observed to gain a proper understanding of how the principal of dialysis functions.

Introduction This lab report titled Introduction to Osmosis and explanatory reactions, was centered around the diffusion across a cellular membrane and how the blood reacted under different solutions concentrations. The diffusion and the osmosis are types of movement that a related to passive transport through the cell membranes. Diffusion is when a solute move from a high concentration area to an area where the concentration is lower. While Osmosis is the movement of water through membrane.

Materials 3 strips of dialysis tubing, measured into 15 cm strips 3 400mL beakers Electric Balance Sugar (sucrose) Graduated cylinder String Distilled water Pipette Labeling tape Stirring rod Procedure Cut the tubing into three strips and set into a beaker to soak Measure the mass of another empty beaker on the electronic scale and press clear. Measure 200 mL of water in the graduated cylinder. Fill the other two beakers with distilled water until all three beakers are at the same level.

The purpose of this investigation lab is to observe osmosis of water into a cell, and also how. The goal of the experiment is to prove that a solution in an area of high concentration will move to an area of low concentration. In this experiment, we used sheep blood, 0.9% NaCl, 10% NaCl, and dH2O water to see what will cause when we add this to the cell. We will then record the rate of diffusion by measuring how did the blood flow into each solution and recording them. First, we placed with the wooden applicator stick, then dip the end into the blood and place tiny drop in the slide to observe what it will do.

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.