3. Explain why half of a cucumber becomes soft if left lying on the kitchen table for a few days but becomes turgid if its cut end is placed in distilled water for the same duration of time?
Answers
Explanation:
The process that happens to both cucumber slices is called osmosis, which is a diffusion of water across the semipermeable membrane the potato slice cells possess. The water will either go into the cells, or come out of the cells, depending upon the water composition of the environment they are placed in.
The first cucumber slice is placed in distilled water, which is a high concentration of almost pure water, definitely higher than that which the cucumber's cells contain. This solution is referred to as hypotonic.
The water will diffuse into the cells of the cucumber, causing them to swell; the cells may be characterized as being "turgid".
The second cucumber slice is left open to the air. This solution, or the lack thereof, may be referred to as hypertonic, meaning the water concentration of the cucumber's cells is higher than that of the environment the potato is placed in.
In this scenario, the water will diffuse out of the cucumber's cells, and evaporate into the surrounding air. The cucumber will assume a characteristic "flaccid" texture, because the cell membrane has separated from the protective cell wall. It will be soft certainly without it's previous rigid structure.
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