1a2 marks
A biologist investigated how surface area affects osmosis in potato cubes.
| Step 1: | Cut two cubes of potato, each with sides of 4 cm in length. |
| Step 2: | Place one cube into concentrated (40%) sucrose solution. |
| Step 3: | Cut the remaining cube into eight equal-sized smaller cubes and place into concentrated (40%) sucrose solution. |
| Step 4: | Record the masses of the cubes at time intervals. |
The results are shown in the graph.
Explain why the potato tissue changed in mass.
1b2 marks
The biologist recorded the masses of the cubes at intervals. Before weighing the cubes at each interval, the biologist blotted the outside of each cube with paper towel.
Explain why.
1c4 marks
During the first 20 minutes the combined loss in mass of the eight small cubes is greater than in the single large cube (as shown in the graph in part a).
Calculate the rate of loss in mass, per cm2, per minute for the single large cube and the eight small cubes during the first 20 minutes.
Give your answers in grams, per cm2, per minute.
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