Question

Which option is true for a fully turgid cell?
a. OP = DPD
b. OP zero
c. DPD = Zero
d. TP = Zero

Answer 1

Hint: In general the word turgidity means, swollen, or bloated, in the plants, for example, the cells absorb water fully and if it is no more capable to absorb any water then we call that as turgid cell, in plants the turgid cell membrane is pushed towards the cell wall, and if not or if it opposite then we call the cell as flaccid.

Complete answer:
In order to explain the turgidity of the cell, I will give the example,
Before that there is a basic terminology that should be explained, diffusion is nothing but movement of liquids from low concentration to high concentrate, normally pure water has more diffusion, if we mix any solute then it becomes the solution, in this diffusion pressure decreases. So the difference between the diffusion of pure water and solute containing water is called a Diffusion pressure deficit. ( DPD)

If a plant cell is placed in a hypotonic solution, water starts to move into the cell, so that cell becomes turgid, and the cell membrane is pushed towards the cell wall and cell got the Turgor pressure, and as the water is diffusing more and more the turgor pressure (TP) increases and the Osmotic pressure (OP) get decreases, at one point the cell is full and it is no more ready to take water in, then in this situation TP = OP.

So if the turgor pressure is equal to osmotic pressure, then no more diffusion occurs in that cell, so the diffusion pressure deficit or suction pressure (DPD) becomes zero.
Hence, the correct answer is option (C).

Note: Diffusion pressure deficit is nothing but the actual thirst of a cell for water and it can be expressed as DPD = OP – TP and this DPD are directly proportional to the height of the plant cell, and the concentration of the solution.