Potato practical - biology Flashcards
1
Q
how do you find out how sugar solutions affect plant tissue
A
- Peel the potato then cut it up into identical cylinders
- Get some beakers with different sugar solutions in the, one should be distilled water, another should be a very concentrated sugar solution
- Measure the starting mass of the cylinders, then leave the cylinders in each beaker for 24 hrs
- Take the cylinders out, pat them dry and measure their masses again
- Calculate the percentage change and plot on a graph
2
Q
dependent variable in this experiment
A
potato mass
3
Q
independent variable in this experiment
A
concentration of the sugar solution
4
Q
control variables in this experiment
A
volume of solution, temperature, time
5
Q
why should you pat the potato dry after taking it out of the solution
A
to remove any excess water
6
Q
why should you peel the potato
A
potato skin can affect omosis
7
Q
why should you use a cork borer to cut the potatoes
A
to make sure theyre all the same diameter
8
Q
what is a potential error that could occur whilst patting down the potatoes
A
you might force water out of the cells
9
Q
why do we find percentage change rather than change in mass
A
so that we can compare
10
Q
method (osmosis prac)
A
- peel potato skin off
- use a cork borer to produce 3 cylinders of potato
- use a scalpel to trim the cylinders to the same length
- measure the length of each cylinder using a ruler, and the mass of each using a balance
- place each cylinder in a test tube. add 10cm3 of 0.5 molar sugar solution to the first test tube
- add 10cm3 of 0.25 molar sugar solution in the next test tube
- add 10cm3 of distilled water to the third test tube
- leave the potato cylinders overnight to allow osmosis to take place - remove the potato cylinders and gently roll them on paper towels to remove any surface moisture
- measure the length and mass of the cylinders again and calculate percentage change
