When onion cells are placed in a 5% table salt solution, the plasma membranes shrink away from the cell walls. This results from the net movement of

Rationale

When onion cells are placed in a 5% table salt solution, the plasma membranes shrink away from the cell walls due to the net movement of water out of the onion cells.

In a hypertonic solution like a 5% salt solution, water moves from an area of lower solute concentration (inside the onion cells) to an area of higher solute concentration (the surrounding solution). This loss of water causes the plasma membrane to retract from the cell wall, a process known as plasmolysis.

A (water into the onion cells) YOUR ANSWER

This choice is incorrect because placing onion cells in a 5% salt solution creates a hypertonic environment. Water would not move into the cells; instead, it would flow out of the cells to balance the concentration gradient of the solutes.

B (water out of the onion cells) CORRECT

This is the correct answer. In a hypertonic solution, water moves out of the onion cells, leading to the shrinking of the plasma membrane away from the cell wall, a phenomenon known as plasmolysis.

C (salt into the onion cells) YOUR ANSWER

This option is incorrect as well because the salt concentration outside the cells is higher than inside. Thus, there is no driving force for salt to enter the cells; rather, the opposite would occur if any movement were to take place at all.

D (salt out of the onion cells) YOUR ANSWER

This choice is also incorrect because the salt concentration is higher in the external environment. There is no reason for salt to move out of the onion cells, as the net osmotic movement is focused on water rather than solutes.

Conclusion

In summary, when onion cells are exposed to a hypertonic solution like 5% table salt, water exits the cells in an attempt to equalize solute concentrations on either side of the membrane. This results in the plasma membrane pulling away from the cell wall, confirming that the net movement is indeed water out of the onion cells, which is the critical factor in osmotic processes.

When onion cells are placed in a 5% table salt solution, the plasma membranes shrink away from the cell walls. This results from the net movement of

When onion cells are placed in a 5% table salt solution, the plasma membranes shrink away from the cell walls due to the net movement of water out of the onion cells.

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