Model Cell Prac
Aim:
The aim was to see the difference between the model cells from when they were
first put into a different solution to see how they have changed in 2 days.
Apparatus:
 Beakers x5
 Onion (cut in half)
 Rubber bands x8
 Sucrose
 Water
 Salt water
 Starch
 Dialysis tube
 Clamps
 Thistle funnel
 Retort stand
Method:
1. Fill beaker with solution
2. Make your cell using your dialysis tube and put solution inside, tying it off
with two rubber bands.
3. Weigh and record the weight of the cells.
4. Place model cell in the solution, in beaker.
5. Make salt water by putting 5 spatulas of salt in, heating and stirring until
salt is almost dissolved
6. Get an onion cut in half, putting one half in water and the other in salt
water.
7. Use the retort stand and Thistle funnel to put glucose in the cell to be put
in the water.
8. Wait for two days
Results
The Weight:
Solutions
Weight At Start (grams) Weight After Two Days
(grams)
Water in glucose
12.6
12.73
Glucose in water
18.25
24.95
Starch in Iodine
15.1
15.94
Onion in salt water- Went from a normal onion to a soft, tender onion.
Conclusion:
1. What is diffusion? Diffusion is when one or more gas particles (or
molecules) move through other gas molecules or particles. For example, if
you sprayed deodorant at one side of the room it is going to move through
the air particles and molecules to get to the other side.
2. What is a semipermeable membrane? A semipermeable membrane is an
object that lets some particles through it but some do not. This is because
its paws are too small to let some molecules in, therefore, the larger ones
bounce off whereas the smaller ones go through.
3. What is the difference between diffusion and osmosis? Osmosis is the
diffusion that whenever is in high concentration, will move try to find a
way to go into a lower concentration.
4. How is Osmosis important to plants and fish? Osmosis determines where
water goes and how it can be controlled this is why it effects plants and
fish.
5. How do sugars and starch enter and leave a cell if they cannot diffuse
across? This is due to osmosis.