B2.1.2 - Osmosis Flashcards
What is osmosis?
The diffusion of water molecules across a selectively permeable membrane
What does osmosis explain?
How water gets in and out of cells
What do water molecules do when a solute is dissolved?
They cluster around the solute molecules
What is water potential?
The concentration of free water particles
What type of water has the highest water potential?
Pure water
When will the water potential be low?
When the water is highly concentrated
Describe the movement of osmosis using key words
Osmosis is the movement of water molecules from a high water potential to a low water potential
What is water potential an example of?
A concentration gradient
How do you increase the rate of osmosis?
You increase the difference in water potential
You decrease the difference the particles need to travel
You increase the surface area
What is turgor pressure?
The pressure that makes a cell rigid
What is a plasmolysed cell?
A cell where the cell contents fall away from the cell wall because it lost its turgor pressure and becomes flaccid
What is lysis?
When a cell takes up too much water, swells and then bursts
What happens when you place an animal cell in a lower concentrated solution?
It fills up and swells due to the water goes into it, and may burst
This is called lysis
What happens if you put an animal cell in a normally concentrated solvent?
Nothing happens
What happens if you place an animal cell in a more concentrated solution?
It becomes crenated
