Osmosis Flashcards
What is the independent variable in osmosis experiments?
sugar solution concentration
What is the dependent variable in osmosis experiments?
change in mass of plant tissue
What are the control variables in osmosis variables?
length of potato cylinder, diameter of potato cylinder, the potato is left in solution
What is the expected result in the osmosis experiment?
distilled water = will gain mass water moves into the cells
concentration solutions = will lose mass = water leaves cells
will be a concentration solution where mass stays same = water has moved in and out of cells equally
What is step one in the osmosis practical?
measure and record the start length and mass of the potato cylinders (usually using a cork borer)
What is step two in the osmosis practical?
place each cylinder into a different concentration of sugar solution
What is step three in the osmosis practical?
leave them for an hour for noticeable results (minimum of 30 minutes)
What is step four in the osmosis practical?
remove the potato, blot it dry then measure and record the final length and mass
What is step five in the osmosis practical?
calculate the change in length and change in mass
What is the equasion used to find change in length/ change in mass?
percentage (%) change = change ÷ initial x 100
Define osmosis
movement of water through a partially permeable permeable membrane from a high water concentration to a low water concentration down the concentration gradient
If water isn’t used is it osmosis?
no
What are the three ways to find out concentration in a cell?
Test 5 concentrations, plot graph of % change against one, where line of best fit intersects x-axis
What tissue could osmosis be performed in?
could be any plant tissue (even eggs)
why do we do % change?
takes into account different start masses (1 mark) therefore more accurate (1 mark)
