water moves in and out of cell along a concentration gradien

water moves in and out of cell along a concentration gradient. how would you design an experiment to determine the solute concentration within cells of a piece of apple?

a. Woud you expect the solute concentrations to be high or low compared to other tissues of the plant? Why?

b. what materials would you need?

c. What would be the steps of your procendure?

d. Would you consider repeating your experiment? why or why not?

Solution

The experiment to determine the solute concentration of the apple cells can be done as below.

Percent change in mass = (final mass – initial mass)/ initial mass * 100

The weight of the apple piece would be less compared to that of before it is placed in the solution. As the solution is hypertonic, water moves out of the apple cells into outside and hence the weight of the apple piece will be reduced. The movement of water out of the apple cells is considered as osmosis.

Osmosis is a phenomenon that occurs when water moves from lower solute concentration to higher solute concentration to make the two sides exist in equilibrium. This process is called diffusion of water. A mathematical model will have to be made to fit into the experimental data for sucrose, water and salt. Effective diffusion coefficients are computed with the concentration of solute using material coordinates of the tissue. The coefficients are calculated by integrating the three differential equations prepared for water, sucrose and salt.

a)

The solute concentration of the apple piece will be high compared to that of other tissues of the plant. It is because, the concentration of sugars will increase in the fruits compared to the leaves.

b)

Apple piece, water, salt, measuring jar and weighing machine

c)

Mentioned above

d)

The experiment cannot be repeated as the water moves out the apple cells and the tissue shrunks. Now, when you keep the piece again in the water, water diffuses again into the cell as the concentration of solute is low and that of water is high outside.