Download Water Potential

Water Potential
Learning Targets
1. I can explain what water potential is and how it
is impacted by Ψs and Ψp.
2. I can design an experiment to determine the
concentration of solutes in a living cell.
a. Ψ =Ψs +Ψp
b. Ψ s= -iCRT
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Water potential
 Solute potentinal of pure water is 0
 As solutes are added to water what happens to the solute
potential?
 Pressure potential does not exist in animal cells, what
structure provides this in plant cells?
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Potato cells in pure water…
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Plant cell in a solution with solutes…
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-7.4 bars
Solute potential = -iCRT
Inside cell: i = 2 (Na and Cl ions both form in solution)
C = 0.15M R = 0.083 liter bars/moles K T = 25 +273= 298K
Outside cell ; All is the same except for C = 0.1M
-4.9 bars
Water moves from higher water potential to lower water potential….therefore it
moves into the cell.
+2.5 bars
How will you determine the solute
potential of your potato cells?
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