Question

Flaccidity is
A. Distended nature of plant cell
B. Percentage gain in volume of the cell due to endosmosis
C. Loss of turgidity
D. Volume of cell in an isotonic solution

Answer 1

Hint: A flaccid plant cell is one in which the plasma membrane is not pressed tightly against the cell wall. This is observed when the plant cell is placed in an isotonic solution wherein the concentration of solutes on the outside is the same as that on the inside of a plant cell.

Complete answer: A turgid cell is a cell that has turgor pressure. The plant that looks healthy has turgid cells. The plant cell stores solutes. Since the inside of the cell has a higher solute concentration than the outside, the water tends to move in. The solution (surrounding the cell) that has a lower solute concentration relative to what was inside the cell is described as hypotonic.
-An isotonic solution refers to a solution wherein the solute concentration is relatively the same as the solute concentration inside the cell. This means that there would be no net movement of water molecules between the two. A plant cell that is placed in an isotonic solution would become flaccid. This condition is called flaccidity. A flaccid plant cell is not swollen and its cell membrane does not press against the cell wall tightly.
-A hypotonic solution is a solution wherein the solute concentration is higher than the solute concentration inside the cell. A plant cell in a hypotonic solution loses its turgor pressure as the water molecules tend to move out of the cell. The cell that has lost its turgor pressure is described as plasmolyzed. A plasmolyzed plant cell is one in which there are gaps between the cell wall and the cell membrane.
Hence, the correct answer is option C, i.e., Loss of turgidity.

Note: When a plant cell is placed in a hypertonic solution, the plant cell loses water and the protoplasm of the cell is pulled away from the cell wall. This leaves space between the cell wall and the cell membrane and the plant cell becomes flaccid. This condition is called flaccidity. During this, the cell loses turgidity. When a plant cell is placed in a hypotonic solution, the plant cell intakes water. When the cell is fully inflated with water, it becomes turgid.