Question

Cell A and cell B are adjacent plant cells. In cell A, ${\Psi }_s=-20\text{bars}$ and ${\Psi }_p=8\text{bars}$. In cell B, ${\Psi }_s=-12\text{bars}$ and ${\Psi }_p=2\text{bars}$. Then

• A. Water moves from cell B to cell A.
• B. Equal amount of water is simultaneously exchanged between cell A and cell B.
• C. There is no movement of water between cell A and cell B.
• D. Water moves from cell A to cell B.

Answer 1

The correct option is A Water moves from cell B to cell A.

Water always move from higher water potential to lower water potential.
Water potential = Osmotic potential + Pressure potential
${\Psi }_w={\Psi }_s+{\Psi }_p$
For cell A ${\Psi }_w\left(A\right)=-20+8=-12\text{bars}$
For cell B ${\Psi }_w\left(B\right)=-12+2=-10\text{bars}$
${\Psi }_w\left(B\right)>{\Psi }_w\left(A\right)$ i.e., $-10>-12$ Thus, movement of water will occur from cell B to cell A.