Investigating the Effects of Different Concentrations of Sucrose Solution on Potato Cells

Investigating the Effects of Different Concentrations of Sucrose Solution on Potato Cells

Aim: to investigate the different effects of various concentrations of

sucrose solution on potato cells.

Introduction:

Osmosis is a special type of diffusion. Osmosis happens when two

solutions of different concentrations are separated by a selectively

permeable membrane. A selectively permeable membrane has holes in it

which are just big enough for water molecules to pass through, but not

the much larger sugar molecules. Water moves across the membrane from

a weak solution (high concentration of water molecules) to a stronger

solution (lower concentration of water molecules). In this case, the

two solutions are the cytoplasm inside the potato cells and the

sucrose solution that I am placing my potato chip in. The partially

permeable membrane is the cell membrane of the potato cells.

When potato chips are placed in pure water, the concentration of water

molecules surrounding the plant is higher than the concentration of

water molecules inside the cytoplasm of the potato's cells. The water

will diffuse into the cell and the cytoplasm by osmosis. This means

the cytoplasm pushes out against the cell wall as it expands slightly

and the cell becomes firm or turgid. The overall effect over time is

for each cell to increase slightly in mass and so the whole potato

chip shows an increased mass. However, if you put a piece of potato

into a sugar solution (where the water concentration around the chip

is lower than the water concentration inside the cytoplasm in the

potato's cells), then water will move out of the cells of the potato

and into the...

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... and also would

help me to spot any anomalous results more easily; with only two

results, it can be difficult to tell which result of the two is

anomalous. In future, I will try to collect three or four sets of

results which should be a great help.

It would also be good to have a control experiment where a potato chip

is placed in distilled water. This would be useful to get a wider

spread of results. I could also try using 0.1, 0.3 0.5, 0.7 and 0.9

mole dm-3, which likewise would give me a wider spread of results to

help me draw improved conclusions and graphs.

Overall, I think that my results were accurate and useful, and my

method was fair, although I could have improved my control of

temperature by placing the test tubes in a controlled environment such

as a water bath, and I should have taken more results.