Membrane Lab Report Example | Topics and Well Written Essays - 1000 words

Membrane - Lab Report Example In animal cells, when the solute concentration is equal on both sides of the membrane, there will be no movement of water molecules. Solutions with this property are said to be isotonic. Hypertonic solutions have higher solute concentrations. When an animal cell is placed in this solution the water molecules will move out of the cell, causing it to shrink. On the other hand, placing an animal cell in hypotonic solutions will cause water molecules to move into the cell, causing it to swell. This is because hypotonic solutions have lower solute concentrations (Freeman, 2010). This forms the basis for the hypothesis of the study: the weights of the dialysis tubings with different solute concentrations will change, showing that osmosis is dependent on the concentration of the solute. Method: Six dialysis tubings were soaked for five minutes in a beaker containing 400 ml of water to soften them. One end of every tubing was tightly tied using floss. Two of the tubings were then each filled with 10 ml of water through the untied end. These were taken to be the control tubings. Two other tubings were each filled with 10 ml of 15% sucrose solution and two other with 10 ml of 45% sucrose solution in the same way as the control tubing. The untied ends on the tubings were tied using floss and then appropriately labeled. The weight of each tubing was measured and recorded. 150 ml of water was put in six separate beakers. The six tubings were then placed separately in the six beakers at the same time. After ten minutes, the dialysis tubings were removed from the beakers and their weights measured and recorded. They were then placed in the beakers again. This step was repeated three more times. Results: The weights recorded during the experiment indicated that the weights of the dialysis tubings with sucrose solutions increased as the experiment progressed as shown in the table below. The table also shows that the average weight of the control tubings changed by a small fract ion. Time (minutes) Average weight of water control tubings (grams) Average weight of tubings with 15% sucrose solution (grams) Average weight of tubings with 45% sucrose solution (grams) 0 10.8195 11.8140 13.3010 10 10.5075 12.1435 14.7325 20 10.4570 12.7600 16.4625 30 10.4345 13.3010 17.8905 40 10.3305 13.6795 19.2070 Table 1: Table showing the average weights of the tubings after ten-minute interval The percentage changes in weights of the tubings as their weights increased or reduced are shown below. The results show that the tubings with 45% sucrose gained the most weight while the control tubings reduced in weight. Time (minutes) % change in average weight of water control tubings % change in average weight of tubings with 15% sucrose solution % change in average weight of tubings with 45% sucrose solution 0 0.000 0.000 0.000 10 -2.884 2.789 16.762 20 -3.350 8.007 23.769 30 -3.558 12.587 34.505 40 -4.511 15.790 44.403 Table 2: Table showing the percentage change in weight of t he tubings after ten-minute intervals The data in the table was used to plot the graph below. It shows visually how the weight of the dialysis tubings changes over time. Figure 1: Graph showing changes in percentage weight changes of the tubings after ten-minute intervals. The x-axis represents the time in minutes and the y-axis represents the % weight change. Discussion: The experiment showed that as the concentration of sucrose increased, the mass of the dialysis tubings also increased. In the control tubing, the change in