Direction and concentration gradients Bradley Benton ABSTRACT In this experiment, we will investigate the effect of solute concentration on osmosis. A semi‐permeable membrane (dialysis tubing) and sucrose will create an osmotic environment similar to that of a cell. Using different concentrations of sucrose (which is unable to cross the membrane) will allow us to examine the net movement of water across the membrane. INTRODUCTION A major determinant of diffusion in a biological system is membrane permeability. Small, uncharged molecules pass through cellular membranes easily, while most and/or charged molecules cannot pass through the membrane. The movement of water across a selectively permeable membrane, like the plasma membrane …show more content…
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. RESULTS INITIAL VOLUME | SUCROSE % | PREDICTION | FINAL VOLUME | BAG #1 10mL | 30 | No water will move | 10 mL | BAG #2 10mL | 30 | No water will move | 7 mL | BAG #3 10mL | 30 | Water will move out | 0 mL | BAG #4 10mL | 3 | Water will move in | 10 mL | | | | | CONCLUSION 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
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.
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.
First, we collected the materials that were needed: 3 beakers, 2 clips, glucose test strips, cooked starch, amylase, and iodine. Then we put 4 pipettes of cooked starch in the small beaker. We then mixed the starch wit h4 pipettes of amylase. The starch will be the leaf; the amylase will be the digestive enzyme. The small beaker represents the head and crop. We then put 4 pipettes of the “macerated” solution from the crop to the soaked dialysis tubing. We filled the large beaker two-thirds full of water and put 4 drops of Lugol’s to the beaker. We then put the dialysis tubing into the large beaker. We recorded data
Osmosis • Introduction This experiment will prove how osmosis occurs by using dialysis bags, the water molecules will move through a semipermeable bag from a higher concentration to a lower concentration of water. Each beaker will represent hypertonic, hypotonic, and isotonic solutions. This experiment will demonstrate the process of osmosis in different solutions. Definitions of the main concepts used in this experiment: - Osmosis is the net movement of water molecules across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
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.
Part A: How does the molarity of sucrose solution inside dialysis tubes affect the percent change in mass of the tube after 20 minutes?
Water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane are equal. The diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called osmosis. The movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms. ("Diffusion And Osmosis - Difference And Comparison | Diffen"). A semi-permeable membrane known as the cell membrane surrounds the living cells of both plants and animals. Both solute concentration and membrane permeability are
The independent variable was the concentration of sucrose in the dialysis tubing we used as a simulated membrane.
With all solutes set at a concentration of 5.00 mg/ml and the MWCO set at 20, filtration stopped at 60 minutes, and the projected completion was 100 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentrations for all solutes was 0.00 mg/ml. With all solutes set at a concentration of 5.00 mg/m and the MWCO set at 50, the filtration completed in 40 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentration for NaCl was 4.81 mg/ml, and 0.00 mg/ml for all remaining
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.
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.
Osmosis is a natural occurrence constantly happening within the cells of all living things. For osmosis to occur, water molecules must move across a semipermeable membrane from an area of low concentration to an are of high concentration. In order to understand osmosis, people must understand the different types of concentrations that can be present within solution. One of them is an Isotonic solution where the concentration of dissolved particles is equal to that of a cell’s. Another is a hypertonic solution where there is a higher concentration of dissolved particles then inside the cell. And lastly there is a hypotonic solution where there are less dissolved particles than inside the cell. As dissolved particles move to a region of lower concentration, water moves the opposite direction as a result of there being less water in the highly concentrated region. In this experiment, gummy bears were placed in salt water, sugar water, and tap water to find the measure of osmosis between the solution and gummy bear.
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 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.