Osmosis

Question 1

What is osmosis?

Answer 1

Net movement of water molecules down a water potential gradient

Question 2

What happens when there is a lower concentration of water molecules

Answer 2

There is a higher concentration of solute molecules

Question 3

What happens when there a higher concentration of water molecules?

Answer 3

There is a lower concentration of solute molecules

Question 4

What happens when plant cells are in a low solute concentration?

Answer 4

Water moves in by osmosis down a water potential gradient. Then the cell wall prevents bursting and a membrane pushes against the wall. The cell is turgid.

Question 5

What happens when a plant cell is in a high solute concentration?

Answer 5

Water moves out of cells by osmosis down a water potential gradient. Plant cell membrane pulls away from cel wall as water leaves. The cell is plasmolysed

Question 6

What happens when an animal cell is in a low solute concentration?

Answer 6

Water moves in by osmosis by down a water potential gradient, animal cell bursts open. It is cytolysed

Question 7

What happens when an animal cell is in a high solute concentration?

Answer 7

Water moves in by osmosis down a water potential concentration gradient. Animal cell shrinks and appears wrinkled. It is crenated

Question 8

What is water potential?

Answer 8

The tendency of water to move from one region to another by osmosis
* In pure water the WP is the highest
* Ad more solute moelecules are added the WP decreases

cell potential = solute potential + pressure potential

Question 9

What is pressure potential?

Answer 9

The hydrostatic pressure to which water is subjected.
* Usually positive and is 0 when cells are in equilibrium

sometimes referred to as turgor or water pressure

Question 10

What is solute potential?

Answer 10

A measure of reduction in the water potential due to the presence of solute molecules
* It is the negative component of water potential

sometimes referred to as the osmotic potential or osmotic pressure