17. Osmosis

What is osmosis?

Osmosis is the movement of water particles from an area of high water concentration to an area of low water concentration down the concentration gradient across a partially permeable membrane.

Define solute:

A substance that dissolve in a given solvent

Define hypertonic solution:

has a high solute concentration, low water concentration

Define hypotonic solution:

Has a low concentration of solute and high water concentration

Define isotonic solution:

has a equal concentration of solute and equal high water concentration

Effect of hypotonic solution on mass:

There is a higher solute concentration inside the cell.

Water moves from a low solute concentration to a high solute concentration so water will move into the cell.

This will lead to an increase in mass.

Effect of isotonic solution on mass:

The solute concentration is the equal inside and outside of the cell.

Therefore there will be no net movement of water.

This will lead to no change in mass

Effect of hypertonic solution on mass:

There is a higher solute concentration outside the cell.

Water moves from a low solute concentration to a high solute concentration so water will move out the cell.

This will lead to an decrease in mass.

How to calculate percentage change:

final mass - initial mass
——————————— x 100
initial mass

What does aquaporin mean?

Aquaporin is a channel protein that allows the transport of water across the membrane.
- It is permeable to water