Question

in the following picture what is tonicity of the solution sounding the elodea leaf?

isotonic
hypertonic
hypotonic
neutral

Explanation:

🆕 New Concept Discovered: Tonicity and Plasmolysis
How water movement affects plant cell shape

Step 1: Analyze the cell's appearance

In the provided image of the Elodea leaf, we can observe that the cell contents (including the chloroplasts and the central vacuole) have shriveled and clumped together in the center of each cell. The cell membrane has pulled away from the rigid outer cell wall. This specific state is known as plasmolysis.

Step 2: Determine the direction of water movement

For a cell to shrink and undergo plasmolysis, water must be leaving the cell. Water moves out of a cell when the concentration of solutes outside the cell is higher than the concentration of solutes inside the cell.

Step 3: Identify the tonicity of the surrounding solution

A solution with a higher solute concentration than the inside of the cell is called a hypertonic solution.

• Isotonic: Equal solute concentration; no net water movement, cell looks normal.
• Hypotonic: Lower solute concentration outside; water enters the cell, making it turgid (swollen).
• Hypertonic: Higher solute concentration outside; water leaves the cell, causing it to shrink (plasmolyze).

Since the Elodea cells are clearly plasmolyzed, the surrounding solution is hypertonic.

Answer:

hypertonic