Question

A and B cells are contiguous. Cell A has OP = 10 atm, TP = 7 atm and DPD = 3 atm. Cell B has OP = atm, TP = 3 atm and DPD = 5 atm. The result would be

• A. No movement of water.
• B. Equilibrium between the two
• C. Movement of water from A to B
• D. Movement of water from B to A

Answer 1

Answer: (C)

Movement of water from A to B

• Diffusion Pressure Deficit (DPD) was originally called as suction pressure. The diffusion pressure (DP) of the solution is lower than the pure solvent is referred to as DPD.
• It is measured in terms of atmosphere. It is the difference between the diffusion pressure of a solution and a pure solvent. DPD can be measured using the formula, DPD = OP - TP, where OP = Osmotic Pressure and TP = Turgor Pressure. Here, the water movement across the concentration gradient will be lower DPD to higher DPD.
  

In the above question it is given as follows,

Cell A : OP = 10 atm,

TP = 7 atm and

DPD = 3 atm.

Cell B : OP = ?

TP = 3 atm and

DPD = 5 atm.

Cell B, OP = DPD + TP

OP = 5 + 3 = 8 atm.

Therefore, cell A DPD = 3 atm,

cell B DPD = 5 atm

In the case of Diffusion Pressure Deficit, water movement will be lower DPD to higher DPD i.e, from cell A to cell B.

So, the correct answer is option C.