Question

question 3 / 10
which statement correctly describes the effect of placing a freshwater plant cell in salt water?

a. the cell will swell because the salt water is hypotonic.

b. the cell will swell because the salt water is hypertonic.

c. the cell will shrivel because the salt water is hypotonic.

d. the cell will shrivel because the salt water is hypertonic.

Explanation:

1. Understand Tonicity: A hypertonic solution has a higher solute concentration (and lower water potential) than the cell's interior. A hypotonic solution has a lower solute concentration (and higher water potential) than the cell.
2. Analyze Salt Water vs. Freshwater Plant Cell: Freshwater plant cells have a relatively lower solute concentration (higher water potential) compared to salt water. Salt water has more solutes (like salt ions) than the plant cell's cytoplasm/vacuole. Thus, salt water is hypertonic to the plant cell.
3. Osmosis Direction: Water moves across a semipermeable membrane (the plant cell's plasma membrane and tonoplast) from an area of higher water potential (inside the cell) to lower water potential (outside, in salt water) via osmosis.
4. Effect on the Cell: As water leaves the plant cell, the protoplast (cell membrane and its contents) will shrink or shrivel away from the cell wall (plasmolysis). This matches option D: the cell shrivels because salt water is hypertonic (causing water to exit the cell).

Options A and B are incorrect because a hypertonic solution (salt water) does not cause swelling (swelling occurs in a hypotonic solution, where water enters the cell). Option C is incorrect because salt water is hypertonic (not hypotonic) relative to the freshwater plant cell.

Answer:

D. The cell will shrivel because the salt water is hypertonic.