Core Practical: Osmosis in Potatoes Flashcards
All 5 cards in this deck
What are the steps to investigate osmosis in potato tissue?
e.g. using distilled water and a concentrated sugar solution- Cut potato cylinders of the same size, blot dry and record the starting mass.
- Place one cylinder in each solution for the same time at the same temperature — e.g. one in distilled water, one in concentrated sugar solution.
- Blot dry, reweigh and work out the percentage change in mass.
What is the equation for percentage change in mass?
percentage change in mass = (final mass − starting mass) ÷ starting mass × 100
On a graph of percentage change in mass against solution concentration, what does the point where the line crosses the x-axis show?
The concentration at which there is no change in mass — it is the same as the concentration inside the potato cells.
In the potato osmosis core practical, why must each potato cylinder be blotted dry before it is reweighed?
To remove solution from the surface, which would otherwise add to the mass and make the mass change wrong.
True or false? Taking repeated readings at each concentration and calculating a mean makes the results of the potato osmosis investigation more reliable.
True. Repeats and a mean reduce the effect of anomalous results.