Diffusion through the Cell Membrane:
Note: The experiment was only done once as studies had to seize due to covid, so I don’t have a lot of data. The draft may seem confusing so I’ll explain better. My aim was to see with 3 different temperatures, the rate of how the h20 in the cell membrane (dialysis tubing) diffused out into the salt water and diluted.
Diffusion through the Cell Membrane:
Abstract:
(Dot point only at this stage)
- To determine the rate of the h2o diffusing out of cell membrane, diluting the salt water in 3 different temperatures.
Materials:
+ Tap water
+ 3 x beakers (small sized)
+ Dialysis tubing
+ 3 x measuring cylinder (500ml)
+ Sodium chloride 30% dissolved
+ fishing wire / string
+ Scissors
+ Ruler
+ 3 x glass stirring rods
+ 3 x transfer pipette
Equipment:
+ Refrigerator
+ Incubator (40°C)
+ Refractometer
Method:
Step one: fill 3 measuring cylinders of 250ml of tap water. Place one into the incubator at 40°C; the other into fridge at 4°C and the last leave our in room temperature.
Step two: Dissolve 30% sodium chloride (do not know the amount of salt that was used) into 250ml of tap water.
Step three: Using your ruler measure the dialysis tubing and cut into 15cm length ways (repeat 2 times).Run the tubing under water to soften so the ends open.
Step four: cut some fishing wire or string to tie one end of the tubing. Then fill tubing with 30mL of room temp tap water. Tie the top with another piece of wire (repeat 2 times).
Step five: cut 3 pieces of wire around 30cm long. With each strand, tie around the top of each dialysis with the other end tied to a stirring rod.
Step six: Before you place the dialysis tubing into the three measuring cylinders, take a reading with the Refractometer. Next place each dialysis into the 3 different temperature cylinders (fridge, room temp and incubator) and place back into their environment.
Step seven: every 5min take out the dialysis tube and swirl the measuring cylinder around to mix the water. Place your pipette into the cylinder and take a small amount of water to place onto the refractometer (repeat this step 7 times). Be sure to record your readings.
Results: in the form of a graph please
10 min:
Room temp 21.5°C – reading: 8.8% (% refractometer reading)
Fridge 4 °C – reading: 9.1%
Incubator 40°C – reading: 8.8%
15 min:
Room temp 21.5°C – reading: 8.8%
Fridge 4°C- reading: 9.1%
Incubator 40°C reading: 8.4%
20min:
Room temp 21.5°C – reading: 8.2%
Fridge 4°C – reading: 9.0%
Incubator 40°C – reading: 8.1%
25min:
Room temp 21.5°C – reading: 8.2%
Fridge 4°C – reading: 9.0%
Incubator 40°C – reading: 8.1%
30min:
Room temp 21.5°C – reading: 8.2%
Fridge 4°C – reading: 9.0%
Incubator 40°C – reading: 8.1%
Conclusion:
- Dilutes faster in warmer water / less in cold water
- Changes seem to stop after 25min