Determining the Water Potential of Potato Cells

Determining the Water Potential of Potato Cells

Results table

Sucrose (1%)

Initial mass of discs(g)

Final mass of discs(g)

Change in mass(g)

Change in mass(1%)

0.0/distilled water

1.82

2.13

0.31

17.8

0.1

1.77

1.84

0.07

3.9

0.2

1.76

1.83

0.07

3.9

0.3

1.86

1.71

-0.15

-8

0.4

1.73

1.47

-0.26

-15

0.5

1.88

1.35

-0.49

-26

Trends and Patterns

There is negative correlation on the graph so water is moving from

high concentration to low. The negative correlation also shows that as

you increase the number of moles of sucrose less osmosis is taking

place as there is a less water molecules in the sucrose (and there is

more in potato itself). Therefore the potato cells are absorbing less

water (and losing more than it takes in as the net flow is going out

of the cell). This shows that the number of moles of sucrose as they

increase there water potential is going down until the water potential

of the potato cells becomes greater than that of the sucrose so the

cell starts to become plasmolysed but w hen the water in the sucrose

is absorbed by the potato the potato cells will become turgid. From

this we are able to estimate how many moles of sugar (sucrose) the

potato contains. From the graph I am able to see that from 0.0 to 0.3

moles of sucrose the sucrose is losing water to the potato cells via

osmosis as the gradient of the water in the potato is less than the

sucrose concentration and so the sucrose is losing water. When the

sucrose concentration is abov...

... middle of paper ...

...maly which is result 4 (0.3 molar solution)

because it was the same as it had a very high value compared to other

results (and because it was identical to the last result taken). I

believe that the anomaly was due to human error which was dude to my

colleague for not removing the oil efficiently or it could also be

that my colleague wasn’t able to cut the potato discs inaccurately

giving them a bigger surface area.

Improvements:-

ü A better weighing scale is needed one that measures to a greater

degree of accuracy e.g. a weighing scale that measures to 0.001 grams

ü Abetter blade or slicer/cutter will help give the experiment a more

accurate surface area, length, width etc which will improve the

results significantly.

ü A more efficient method for removing the oil as this will also

improve the results.