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Osmosis practical in artificial bags in various sucrose concentrations:

Hi there,

can anyone help please? I'm supposed to write a prediction of the practical above and include those words: ) Predict whether cells will gain or lose water; explain your ideas using the terms: water potential, hypertonic, hypotonic and isotonic. I don't understand the prediction of the results in terms of water potential. Can anyone please advise for a) to e) what will happen in terms of water potential for each solution?

I'm up so far:

After setting up the experiment my predictions of the results are as follows:
a) 1st artificial cell in 0.1 mol / dm3 of sucrose solution, which is hypotonic water molecules will move in by osmosis down the water potential gradient
b) 2nd artificial cell in 0.2 mol / dm3 of sucrose solution, which is hypotonic water molecules will move in the artificial by osmosis down the water potential gradient
c) 3rd artificial cell in 0.4 mol / dm3 of sucrose solution there will be no overall movement of water molecules as both concentrations are the same - of an artificial bag and the sucrose solution
d) 4th artificial cell in 0.8 mol / dm3 of sucrose solution, which is hypertonic water molecules will move out of the artificial cell by osmosis hypertonic
e) 5th artificial cell in 1.0 mol / dm3 of sucrose solution, which is hypertonic water molecules will move out of the artificial cell by osmosis up the water potential gradient


Thanks
During osmosis, water will travel from an area of high water potential to low water potential, i.e. from a place with lots of water and little solute to a place with little water and lots of solute. It's a bit like diffusion, but with water molecules.

If the solution is hypertonic to the cell, it has a greater solute concentration and lower water potential. Water will move out of the cell to achieve an equilibrium. The water potential of the solution will increase (gaining water) and the water potential of the cell will decrease (losing water).
If the solution is hypotonic to the cell, it has a smaller solute concentration and higher water potential. Water will move into the cell to achieve an equilibrium. The water potential of the solution will decrease (losing water) and the water potential of thee cell will increase (gaining water).
If the solutions are isotonic, their water potential is the same and there will be no net water movement, so water potential will not change.
(edited 3 years ago)
Reply 2
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sniza
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5
Thanks for explanation! I’m finally getting it. You saved me:-)

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