Posted by Saira on .
Hey i have a mid term today at 3 , and this one sample question my prof posted online. If someone can please show me how to get the answers i would really appreciate it:
A plant cell is found to have a Ψs =  0.7 MPa and a Ψp = 0.5 MPa.
Is this cell turgid? (yes or no) (1 mark)
Yes
b. What is the Ψw of this cell?
0.2
c. If this cell were placed in a large beaker of solution (at atmospheric pressure and with a Ψs =  0.3 MPa), would water enter or leave the cell? Assume that no solute can cross the plant plasma membrane in either direction and that the volume of neither body of water changes significantly.
leave(down Ψw gradient)
d. Once the cell in c. has come to equilibrium with the beaker solution (again assuming that no solute crosses the plant plasma membrane in either direction and that the volume of neither body of water changes significantly), what will be the Ψp within the cell?
0.4
(0.3 MPa = 0.7 MPa + 0.4 MPa)

The equation is :
Ψw = Ψs + ΨP

Plant Physiology 
Saira,
Sorry entire thing didn't get posted:
a.So the answer for is the cell turgid?
Yes
B. What is the Ψw of this cell?
0.2
C. If this cell were placed in a large beaker of solution ( at atmospheric pressure and with a Ψs =  0.3 MPa. would the water enter or leave the cell?
Assume that no solute can cross the plant plasma membrane in either direction and that the volume of neither body of water changes significantly.
Leaves
D.Once the cell in C. has come to equilibrium with the beaker solution( again assuming no solute can cross the plant plasma membrane in either direction and that the volume of neither body of water changes significantly.What will the Ψp be within the cell?
0.4
(0.3 MPa = 0.7 MPa + 0.4 MPa) 
Plant Physiology 
Saira,
Okay in understand everything except D....SOMEONE PLEASE HELpp