F4 BIO實驗問題

You mean the solutions were poured into the middle of the potato?


This experiment aims at proofing the differential permeability of living cell membranes.

X: Water level dropped, potato became turgid / 硬硬地 / 有彈性
Y: Water level increased, potato 乾乾地 / soft / the cells were plasmolysed.
Z: Water level dropped in the potato cup dropped, and it is the same as those in the container.

X: Because cytoplasm of the potato has a lower water potential than distilled water, a water potential gradient appeared. Thus water is absorbed into the potato by osmosis, and therefore the water level is lowered.

Y: As the sucrose solution is more concentrated than the cytoplasm, water is drawn from the cell by osmosis. Therefore the cell 扁扁地 and sucrose solution level increased。
Note that the cell is not completely 扁 because the cell wall is still supporting it.

Z: As Z is boiled, its cell membrane has denatured and it is dead. So the sucrose solution is freely permeable, and thus, the cytoplasm leaks out, and the sucrose solution is allowed to enter the cell. Therefore, by diffusion, the cytoplasm and the sucrose solution are mixed together. The level of the solution in the potato cup and the container is therefore the same.