Question

A student wants to do an investigation to illustrate the role osmosis plays in maintaining homeostasis inside the cell. The student wants to use a freshly cut slice of raw potato in the investigation.

What would be the best way for the student to use the potato to demonstrate how osmosis maintains homeostasis inside of cells?

A.
Cut the potato slice in half. Place one half on a counter and place the other in a 10% salt solution. Wait several hours, and then make observations of how flexible each slice is.

B.
Weigh the potato, leave it on a counter overnight, and weigh it again in the morning. Place the potato in a beaker of fresh water for several hours, and weigh it a final time.

C.
Taste a small piece of the potato slice. Record any observations. Place the potato slice in a 10% salt solution for several hours. Remove the potato slice, cut off a small piece, and taste it.

D.
Cut the potato slice in half. Place one potato in a glass of fresh water. Place the other in fresh water with food coloring added. Remove the potatoes after several hours and note any color differences.

Answer 1

B

Weighing the potato, letting it lose water, then placing it in fresh water and reweighing shows quantitative water loss and then uptake by osmosis. The changes in mass demonstrate how water movement helps cells restore/maintain internal balance (homeostasis). Options C is unsafe, D tests dye diffusion rather than osmosis, and A’s control (left on a counter) is not a proper comparison to a salt solution.