Question

What happens to an onion cell after being in salt water then moved to pure water

Answer 1

In salt water, an onion cell undergoes plasmolysis as water leaves the cell, which can lead to cell death. When moved to pure water, the cell can swell, become turgid, and potentially burst due to the influx of water.

Step-by-step explanation:

When an onion cell is first placed in salt water, there is a higher concentration of solute outside the cell compared to the inside. Water molecules naturally move from areas of lower solute concentration to higher solute concentration through a process known as osmosis. In this scenario, water will leave the cell, resulting in plasmolysis where the protoplasm shrinks away from the cell wall.

This can cause cell death and is why salt is used for food preservation. However, if the same onion cell is then moved to pure water, the outside environment now has a lower solute concentration than the inside of the cell. Consequently, water will move into the cell, potentially causing the cell to swell and become turgid. If too much water enters, the cell can burst, a process known as lysing.

Answer 2

Vacuole within the onion cell expands, pushing the cytoplasm outwards

Step-by-step explanation:

If an onion cell that is placed into an external solution whose solute concentration is lower (hypotonic), i.e. having less salt, than that of the cytosol (because it had previously been in a salty solution), the vacuole within the cell will expand, pushing the cytoplasm outwards.