osmosis Flashcards
Define osmosis
the net movement of water molecules from a region of their higher water potential (DILUTE SOLUTION) to a region of their lower water potential (CONCENTRATED SOLUTION)
through a partially permeable membrane.
What is high water potential (dilute solution)?
a solution that has more free water molecules compared to a solution with low water potential.
What happens when you place a plant cell in a dilute solution?
Water enters the cell by osmosis and becomes turgid/tight
What happens when you place a plant cell in a concentrated solution?
Water exists the cell by osmosis and the cell becomes flaccid.
In EXTREME cases, large amounts of water leaves the cell and the cell then becomes PLASMOLYSED.
What happens when you place an animal cell in a dilute solution?
In high water potential, or diluted solutions (i.e pure water), water moves in by osmosis and can cause the cells to burst (called lysis) since there is no cell wall to withstand the water pressure.
What happens when you place an animal cell in a concentrated solution?
animal cells don’t have a defined shape, therefore if water moves out of them—the membrane will shrivel up and become CRENATED.
Solvent vs solute
solute = substance that is being dissolved
solvent = dissolving medium
Isotonic, hypertonic and hypotonic solutions
Isotonic solutions are when the solvent are solute are equal, and they travel in and out of the cell equally
Hypertonic solutions are when there are more solutes than solvent OUTSIDE the cell. Hence, there is a higher concentration of solvent inside the cell, so the solvent travels out of the cell (and the cell will shrink)
(low concentration on the outside)
Hypotonic solutions are when there is little solutes OUTSIDE the cell–causing a higher concentration (dilute solution) outside the cell. So the solvent flows into the cell, and the cell will expand
(low concentration on the inside)
