Two potato cubes each 1 cm3 in size, were placed separately in two containers (A and B), the container A having water and the other (B) containing concentrated sugar solution. After 24 hours when the cubes were examined, those placed in water were found to be firm and had increased slightly in size and those placed in concentrated sugar solution were found to be soft and somewhat decreased in size. Use the above information to answer the questions that follow:

1. Account for the firmness and increase in the size of the potato cubes placed in water.

2. Account for the softness and decrease in size of the potato cubes which were placed in sugar solution.

3. Name and define the physical process being investigated in this experiment.

Answers:

1. In this case, the solution outside the cell has a lower concentration than the fluid inside the cell. As a result, water molecules from the outside will enter the cell (endosmosis). This causes stiffness and increases in the size of the potato tubes when placed in water.

2. In this case, the solution outside the cell has a higher concentration than the fluid inside the cell. As a result, water molecules from inside the cell will be released (exosmosis). This causes a softening and a decrease in the size of the potato potato when added to the sugar solution.

3. Osmosis is the process involved in this experiment and it is the movement of water molecules from their region of higher concentration to their region of lower concentration through a semi-permeable membrane