In this investigation you will be using Potatoes and different sucrose solution concentration to observe the effects of osmosis.
Solution
Mass of potato at start
Mass of potato at end
Increase (+) or decrease (-) in mass (g)
0%
10%
40%
Questions
1 Look at the results for each piece of potato in each solution
a Was there a higher concentration of solutes in the water or in the cells of the potato, for the 0%, 10% and 40% solutions?
b In which direction was the overall movement of water. For the 0%, 10% and 40% solutions?
2 Now look at the results for the piece of potato in 40% sucrose solution. Explain the change in mass, include the words:
concentration gradient, net movement, osmosis and semi permeable membrane.
3 Explain why plant cells store glucose in the form of starch, which is a much larger molecule.
1. Place the potato on the cutting board and press in the cork borer to cut through the potato. Remove the cork borer and push out the potato cylinder.
2. Use the same method to cut a second potato cylinder.
3. Weigh each potato cylinder to an accuracy of two decimal places. Record your measurements in a table like the one shown.
4. Place one potato cylinder in water and one in the sucrose solution. Leave until later in the lesson.
5. Take each piece of potato out and blot them both dry with a paper towel.
6. Reweigh the potato cylinders and add the measurements to the results table.
7. Calculate the change in mass to complete the table.
