Tonicity and Osmoregulation Practice Test

Two groups of identical animal cells (internal solute concentration 0.25 M) are placed into separate solutions. Group X is placed in 0.25 M glucose; Group Y is placed in 0.25 M sucrose. The membrane is permeable to water and glucose but not to sucrose. After 15 minutes, Group X cells are larger than at the start, while Group Y cells show little change. Which outcome is most likely to explain why Group X swelled?

A student places identical animal cells (internal solute concentration 0.30 M) into three beakers separated by membranes permeable only to water. Beaker 1 contains 0.10 M sucrose, Beaker 2 contains 0.30 M sucrose, and Beaker 3 contains 0.50 M sucrose. After 10 minutes, the student observes no change in the cells in Beaker 2. Assume sucrose does not cross the cell membrane and no active transport changes solute levels during the trial. Which outcome is most likely for the cells in Beaker 3 compared with their initial volume?