Data Analysis Activity:
Understanding Solutions and Cell Environments
In this activity, we will examine how potato cores (cylindrical sections of potato) react when soaked in five different solutions for 24 hours.
A solution is made up of two parts:
The concentration of the solution tells us how much solute is mixed with each volume of water. In this activity, we will express this concentration as a percentage.
Hypertonic
Isotonic
Hypotonic
When we discuss how substances move in and out of cells, we need to understand three types of solutions:
Hypertonic Solution: Has a higher concentration of solutes compared to another solution.
Isotonic Solution: Has equal concentrations of solutes compared to another solution.
Hypotonic Solution: Has a lower concentration of solutes compared to another solution.
These solutions don’t exist independently; they must be compared to one another across a semi-permeable membrane (like a cell membrane).
To understand how these solutions affect cells, think about them in terms of comparison:
If the solution inside the cell (intracellular) is hypertonic: The solution outside the cell (extracellular) is hypotonic.
If the intracellular solution is hypotonic: The extracellular solution is hypertonic.
If both the intracellular and extracellular solutions are isotonic: They have equal concentrations.
Impact of Solutions on Intracellular Fluid
When a cell is placed in one of three types of solutions—hypertonic, isotonic, or hypotonic—the fluid inside and outside the cell will react in one of three ways:
1. Water Enters the Cell:
If the solution outside the cell is hypotonic (lower concentration of solutes), water moves into the cell.
This causes the cell to swell and its volume to increase.
You can measure this increase through a rise in the cell’s mass.
2. Water Leaves the Cell:
If the solution outside the cell is hypertonic (higher concentration of solutes), water moves out of the cell.
This causes the cell to shrink and its volume to decrease.
You can measure this decrease through a drop in the cell’s mass.
3. No Net Movement of Water:
If the solution is isotonic (equal concentrations of solutes), an equal amount of water enters and leaves the cell.
In this case, the volume and mass of the cell remain mostly unchanged.
Remember, water always moves toward the hypertonic solution, whether it’s inside or outside of a cell.
Wherever water goes, it carries mass with it, which affects the overall mass of the cell.