Biology – 3.2 Osmosis | e-Consult

a) The table shows the percentage change in the mass of potato cylinders after being immersed in solutions of different concentrations of sodium chloride (NaCl) for 24 hours.

b) The table demonstrates a positive correlation between the concentration of NaCl and the mass change of the potato cylinders. In terms of osmosis, this means that as the concentration of NaCl in the surrounding solution increases, the mass of the potato cylinders increases. This is because the NaCl solution creates a lower water potential outside the potato cells compared to the water potential inside the potato cells. Therefore, water moves into the potato cells by osmosis, increasing their volume and consequently increasing the mass of the potato cylinders. The higher the concentration of NaCl, the greater the difference in water potential, and the more water moves into the cells.

c) One source of error in this experiment could be variations in the size or shape of the potato cylinders. If the cylinders are not all the same size, they will have different volumes, and this could affect the amount of water they absorb. This would lead to inaccurate mass measurements and potentially skew the results. To mitigate this error, it would be important to use potato cylinders of uniform size and shape. Alternatively, the mass of the cylinders could be measured before the experiment to account for any initial size differences.