Question

When a plasmolysed cell is placed in a hypotonic solution then water will move inside the cell this will happen due to which force?
A. Diffusion pressure deficit
B. Osmotic pressure
C. Wall pressure
D. None of the above

Answer 1

Hint: Plasmolysed cells can lose water in hypertonic solution by the process of plasmolysis while deplasmolysis can occur in hypotonic solution. Turgor pressure is negative in plasmolysed cells. By the process of diffusion molecules move under a concentration gradient. Osmosis is the process by which molecules move from higher concentration to lower concentration through semi permeable membranes.

Complete answer:
The process by which cells lose water in hypertonic solution is called plasmolysis. In hypotonic solutions, reverse processes such as deplasmolysis or cytolysis, can occur in the cell. Due to this external osmotic pressure and net flow of water into the cell lowers down. Protoplast of plasmolysed cells has no turgor pressure and is also shrunken. When the plasmolysed cell is placed in water, endosmosis occurs and protoplasm of the cell resumes its original shape.
 Endosmosis is the process by which water moves outside the cells when placed in a hypotonic solution. Due to this cell swells. Exosmosis is the process by which water moves outside the cell when placed in a hypertonic solution. Cell becomes flaccid by this process.
Turgor pressure is negative in plasmolysed cells. Diffusion pressure deficit will be maximum in this condition. Due to DPD water enters into the cell when it is placed in a hypotonic solution. When the cell becomes fully turgid the entry of water in the cell stops.
From the above information we can say that water will move inside the plasmolysed cell by Diffusion pressure deficit force in a hypotonic solution.

So, option A is the correct answer.

Note: When the plant cell is placed in an isotonic solution, the condition is called as flaccidity. Protoplast of flaccid cells has no turgor pressure. Due to turgor pressure plants stay firm and erect, without turgor pressure plant will wilt. Stomata in the leaf help to keep water in the plant so that it does not dry out. Animal cells shrink during exosmosis.