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Journal 6

How Things Get into and out of Cells
To solve the problem below, you must write a clear and convincing justification for accepting one of the possible answer choices as the best or most appropriate and for rejecting each of the other choices as less appropriate. Your reasons for rejecting choices are just as important as your reasons for choosing the best answer.
A Ligustrum plant cell is exposed to an aqueous solution having sodium and chloride concentrations higher than the sodium and chloride concentrations of the cell interior. After thirty minutes, a biologist observes the cell under a microscope and states that the cell shows no evidence of having lost water. Which of the following best explains the observation?
1
 The cell membrane is not permeable to either sodium or chloride.
2
 The cell is surrounded by a rigid cell wall.
3
 The cell protected itself by actively transporting sodium across the cell membrane into the external solution.
4
 A plant cell, being different from an animal cell, cannot tolerate high concentrations of sodium and chloride and dies within 5 minutes.
5
 The cell interior contains a variety of solutes in addition to sodium and chloride.