Water Potential of Potato Cells

Water Potential of Potato Cells

Aim:

To demonstrate the Water Potential of Potato Cells.

Objectives:

· To show the water potential of potato cells using various measured

concentrations of a sucrose solution and pieces of potato.

· To record and analyse data to verify observed results.

·

The method and procedure was carried out as per instruction sheet.

Observations:

The experiment shows that the lower the concentration of the sugar

solution, in the Petri dish, the mass of the potato increased.

This is because the water molecules passed from a high concentration

in the water, to a low concentration, in the piece of potato.

Therefore, the

potato in higher water concentrations will have a larger mass than in

higher

sucrose concentrations. i.e. The potato pieces are shown to have water

potential.

The attached graph shows the concentration of the sucrose solution

plotted against the average mean change in mass.

At point A the graph shows that no change in mass, of the potato,

would have have occurred had we used a 0.2 (m) sucrose solution. This

suggests that the concentration of water inside the potato would have

been equal to the solution outside the potato.

At point B (plain water), there is no indication that the cell is

increasing in mass. This is because the cell is fully turgid and no

more water can enter.

At point C (highest sucrose - lowest water concentration), there is no

indication that the cell is decreasing further in mass. This is

because the potato has become flaccid and no more water can leave the

cell. The potato is said to be plasmolysed.

Conclusions:

There is a pattern on the graph, and data table, which shows that as

the concentration of the sucrose solution increases, the potato's

percentage change in mass decreases.