Question

Three lab groups carried out an experiment to identify the correct molarities for five solutions. Each unknown contained one of the following sucrose concentrations: 0.0 M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, and 1.0 M. Each data entry represents the average of 3 sample replications of 1 cm3 sweet potato cubes expressed as percent change in mass after an overnight (24 hr) soak in the unknown solutions. From the data given, which statement most accurately describes what is occurring in response to a particular unknown solution.
A) Unknown solution E contains the highest concentration of sucrose and the change in mass is due to the active transport of sucrose into the cell in exchange for water molecules.
B) Osmosis of water molecules from unknown solution A likely caused the increase in mass observed.
C) Passive transport of sucrose out of the potato cells explains the change in mass observed for unknown solution F.
D) Unknown solution C represents a sucrose molarity slightly lower than the molarity of sweet potato cells, thus water is transported out of the cells.

Answer 1

Answer:

Osmosis of water molecules from unknown solution A likely caused the increase in mass observed.

Explanation:

Osmosis can be described as a process in which water molecules move from a region of higher concentration to a region of lower concentration along a concentration gradient. So this process does not require energy.

As we observed that there was an increase in the mass of the sweet potato, we can infer that this increase in mass occurred due to osmosis as the concentration of water was more outside the cell as compared to inside of the cell.

Answer 2

Answer:

The potato in the 20% solution remained the same because it was an isotonic solution. . The picture depicts a plant cell in an isotonic solution in which water is both entering and leaving the cell to maintain homeostasis.