The Effect of Different Sugar Concentrations on Potatoes

The Effect of Different Sugar Concentrations on Potatoes

Aim: To investigate the effect of different sugar concentrations on

potatoes.

Osmosis is defined as the net movement of water molecules from a

region in which they are highly concentrated to a region in which they

are less concentrated. This movement must take place across a

partially permeable membrane such as a cell wall, which lets smaller

molecules such as water through but does not allow bigger molecules to

pass through. The diffusion of water molecules will continue until it

reaches equilibrium. This means that the molecules are randomly

distributed throughout, leaving no area of lower or higher

concentration.

Plant cells always have a strong cell wall surrounding the cell

membrane. When they take up water by osmosis they start to swell, but

the cell wall prevents them from bursting. Plant cells become "turgid"

when they are put in dilute solutions. Turgid means swollen and hard.

The pressure inside the cell rises and eventually the internal

pressure of the cell is so high that no more water can enter the cell.

On the other hand, when plant cells are placed in concentrated sugar

solutions, they lose water by osmosis and become "flaccid." This is

exact opposite of "turgid". The contents of the potato cells shrink

and pulls away from the cell wall. These cells are said to be

“plasmolysed”.

In my experiment, I will analyse the effect of various concentrations

of sugar solution on the potato slices and will use the following

equipment:

Equipment and Materials:

· Dried potatoes.

· Kitchen knife.

· Ruler.

· Test tube rack.

· Test tubes.

· Concentrated solutions.

· Measuring cylinder.

· Water.

· Balance scales.

· Stopwatch.

· Clean tile.

· Marker.

· Paper towels.

To create a fair test conditions, certain aspects of the experiment

will have to be kept the same whilst one key variable is changed. I