The diagram shows four experiments used to investigate movement of substances across dialysis tubing. This tubing is a partially permeable membrane which allows both glucose and water to pass through it. Which row in the table shows the experiment(s) where there will be movement of glucose through the partially permeable membrane and the experiment(s) where there will be movement of water through the partially permeable membrane?

Answer:

9) E

Experiment 1 – Movement of water but no movement of glucose
There is distilled water in both the tubing and in the test tube. Even though there is no concentration gradient, water molecules will still move across the membrane. Since there is no glucose, there will be no movement of glucose.

In experiments 2, 3 and 4, there is glucose and water molecules present. Hence, water and glucose molecules will move across the the membrane.