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.
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.

B.
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.

C.
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.

D.
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.

Answer 1

D.

Weighing the potato, letting it lose water, then placing it in fresh water and weighing again gives a measurable change in mass from water loss and then water uptake by osmosis. This directly demonstrates how cells gain or lose water to maintain internal balance (homeostasis). (A is unsafe, C shows diffusion of dye not osmosis, and B uses a poor control and subjective flexibility observations.)