Q. The values of osmotic potential ($\pi)$ and pressure potential ($\rho$) of cells A, B, C and D are given below. [table] Cell | $\mathbf{\pi}$ | $\mathbf{\rho}$ ; A | -1.0 | 0.5 ; B | -0.6 | 0.3 ; C | -1.2 | 0.6 ; D | -0.8 | 0.4 [/table] Identify the correct sequence that shows the path of movement of water from among the following.
A) $D \rightarrow C \rightarrow A \rightarrow B$
B) $B \rightarrow D \rightarrow A \rightarrow C$
C) $B \rightarrow C \rightarrow D \rightarrow A$
D) $C \rightarrow B \rightarrow A \rightarrow D$
Explanation
The movement of water occurs from low DPD cell to high DPD cell. DPD is equal but opposite to water potential (algebraic sum of solute or osmotic potential and pressure potential). [table] Cell | Water potential (osmotic potential + pressure potential | DPD ; A | -1+0.5=-0.5 | +0.5 ; B | -0.6+0.3=-0.3 | +0.3 ; C | -1.2+0.6=-0.6 | +0.6 ; D | -0.8+0.4=-0.4 | +0.4 [/table] So, the correct sequence of the path of movement of water is $B \rightarrow D \rightarrow A \rightarrow C$.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.