Osmosis Lab Report

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.

Purpose: The purpose of this lab is to familiarize you with osmosis and, specifically, what happens to cells when they are exposed to solutions of differing tonicities.

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.

In this lab we found out that the dialysis bag contained more fluids inside it. This can happen because sucrose is small enough to pass through the selectively permeable membrane. Some errors that might have been encountered during the lab could have been the fact that some of the dialysis bags were not tightly tied with the dental floss, or that the wrong substance was used. Another possible source of error was if the carrot strips had been dehydrated from the beginning of the experiment or were already

Three peaks are observed in Figure 1 (concentration of glucose vs. elution volume) which was expected due to the results in table 4 that show intervals of elution. The intervals of the elution are represented as peaks on the graph. The intervals are due to the glucose molecules that enter the beads of the column causing the glucose molecules to elute slowly. Two peaks are observed in Figure 2 (concentration of starch vs. elution volume), which was not expected. One peak was expected for the

Then we inverted the tubes so an air bubble would form in the little tube that is now upside-down. Now that we know what to do, we marked the little tube 2/3 full. One tube was filled to that line with glucose solution, another with fructose solution, sucrose solution and the last one with water. Next, the little tubes were topped off with a yeast solution. Then we slide a big tube over the little one and completed the inversion, this is done for every little test tube. After they are all inverted our group measured the bubble present at the top of the little tube. Then we put all of the inverted test tubes into a hot water bath for 20 minutes. After 20 minutes we took the tubes out and measure the air bubbles in the tubes. Next, we recorded the data calculated the net change from the beginning of the experiment to after the hot

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 correct syringe is used to place 10 cm3 of the first glucose solution into the boiling tube.

The first experiment begun by filling a 600-ml beaker, almost to the top, with water. Next, a 10-ml graduated cylinder was filled to the top with water. Once water was added to the beaker and graduated cylinder, a thumb was placed over the top of the graduated cylinder. This would ensure that no water was let out and no bubbles were let into the graduated cylinder. Next, it was turned upside down and fully submerged into the beaker. Then, a U-shaped glass tube was attained. The short end of the glass tube was placed into the beaker with the tip inside of the graduated cylinder. Next, a 50-ml Erlenmeyer flask was received. After, 10-ml of substrate concentration and 10-ml of catalase/buffer solution were placed into the flask. A rubber stopper was then placed on the opening of the flask. After adding these, the flask was held at the neck and spun softly

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.

All cells in the human body are surrounded by a plasma membrane made up of lipids and proteins which form a barrier. The proteins and lipids in the membrane occupy different roles. The lipids create a semipermeable barrier and the proteins are part of a cross membrane transport. To pass through the membrane a substance goes through a transport known as diffusion. Diffusion is movement of molecules from a high area of concentration to an area of low concentration. There are two different forms of diffusion. One example of diffusion is known as simple diffusion, an unassisted movement of dissolved substances through a selectively permeable membrane (Marieb pg. 54). The

The concentration of a solute affects the rate of osmosis over time, in a way where, the higher the concentration of a solute, the faster the rate of osmosis. This happens because, in a semi-permeable membrane the water is the only through that can move through. In this case our solute is sugar, and sugar cannot fit through the pores in the membrane. When there is more sugar the difference in concentration is greater. That difference makes all the molecules want to move faster. That results in osmotic pressure being built. The sugar tries to get through the membrane, but the pores don’t accommodate it. That means that the water can only go through less pores because more sugar is blocking the pores. The water that goes through the few pores, ends up clumping up near the open pores and, rushes into the membrane faster. That results in the rate of osmosis being faster.

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.

Group 1 received 107% for 0.0m, 109% for 0.25m, 112% for 0.5m, and 126% for 0.75m. Group 2 received 100% for 0.0m, 107% for 0.25m, 116% for 0.5m, and 117% for 0.75m. Group 3 received 100% for 0.0m, 106% for 0.25m, 114% for 0.5 m, and 117% for 0.75m. Group 4 received 100% for 0.0m, 106% for 0.25m, 113% for 0.5m, and 116% for 0.75m. Group 5 received 98% for 0.0m, 105% for 0.25m, 110% for 0.5m, and 115% for 0.75m. Group 6 received 104% for 0.0m, 108% for 0.25m, 111% for 0.5m, and 104% for 0.75m. The trend line that occurred for the rate of osmosis was an upward increase as the solute concentration increased.

Each bag was then placed in their own beaker, containing 200 mL RO H2O for beakers #1-3 and 200 mL 30% sucrose solution for beaker #4. The bags were then taken out every 15 minutes to be weighed over an hour to record any