Question

Two cells A and B are contiguous. Cell A has osmotic pressure 10atm, turgor pressure -7 atm, and diffusion pressure deficit 3atm. Cell B has osmotic pressure 8atm, turgor pressure -3atm, and diffusion pressure deficit 5atm. The result will be
A) Movement of water from cell B to A
B) No movement of water
C) Equilibrium between the two.
D) Movement of water from cell A to B

Answer 1

Water moves within the cells of plants through the simple process of osmosis. However, when there is a pressure experienced on one side of a membrane, this process can be stopped. The pressure that is calculated in plants is called the water potential.

Complete answer:
The osmotic potential, or the minimum pressure required to stop the inflow of water, is regulated by the cell walls that prevent the plant cells from expanding beyond a certain point. Pressure experienced when the plants cells are full, is the turgor pressure, built by water being stored in the main vacuole.
To enable the flow of water between cells, they have to have a different water potential, and this flow will be directional from the higher to the lower potential.

As the two cells have different osmotic pressures, water will flow. Option B is incorrect.
They are also not in a state of equilibrium, option C is therefore incorrect.
Cell B has a higher diffusion pressure deficit than cell A. this means that water will not flow from B to A. >Option A is incorrect.
As A has a lower diffusion pressure deficit than cell B, it has a higher water potential, so water will flow from cell A to cell B. Option D is correct.

Hence the correct answer is option ‘d’.

Note: While turgidity is the state in which a plant cell vacuole is full of water and exerting pressure against the cell wall, when the cells lose water and shrink away from the cell water they are sent to be undergoing plasmolysis.