comparing the water potential of potato tuber cells from baking and sweet potato- 3 Flashcards
comparing the water potential of potato tuber cells from baking and sweet potato
what is the water potential?
is a measure of the tendency of water molecules to pass from one place to another
Describe the method used for this experiment?
- label 6 McCartney bottles, 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 moldm-3 of sucrose solution. repeat with another 6 bottles
- use the 1.0mol dm3 solution and water to make up 20cm3 of sucrose solution of each of the above concentrations
- using a borer, cut 12 potato chips, all of equal length (4cm)
- blot the potato chips dry using a paper towel, until it no longer wets the paper
- weigh each potato chip and place onto a labelled paper towel which is numbered to indicate which sucrose solution each potato chip will be placed in and record the initial masses in the results table.
- quickly transfer each potato chip from it’s square of paper towel to it’s bottle with the same number
- Using a stopwatch, leave the potatoes in the sucrose solution for 20 minutes, them remove suing a sieve and blot dry with a paper towel
- record the final mass of potatoes and plot into table
- calculate the change in mass then percentage change in mass
- plot a graph of your results.
how do we calculate the % change of initial mass?
change in mass/ change before x 100
How would the graph be plotted?
X axis = sugar concentration
Y axis = Average % change of initial mass
(should get negative and positive results)
what is the isotonic point?
where the line hits the X axis -
why did we use the same variety of potato chips?
why did we remove the peel of the potato, how could it have affected osmosis?
why did we need to prepare potatoes of the same length?
why did we blot the potatoes dry?
to remove sucrose solution, as it would add to the weight
