Osmosis

Question 1

Water potential

Answer 1

The tendency of water molecules to enter or leave a system. (Causes pressure KPa)

Question 2

What has the highest water potential

Answer 2

Free water, which means it has the greatest potential energy and is completely free to move

Question 3

What does adding solute do to the water potential

Answer 3

It decreases the water potential as there would be less free water molecules so has a negative value

Question 4

Water potential in animal cells

Answer 4

Is only related to the concentration of the solution. The higher concentration of the solution the lower solute potential and lower tendency of water molecules to move out of the solution

Question 5

What is the extra factor of plant cells to influence water movement in and out of cells

Answer 5

Cellulose cell wall

Question 6

Explain how a plant cell becomes turgid

Answer 6

If there is water around a plant cell, water will diffuse in via osmosis into the vacuole causing it to expand

This pushes the cytoplasm against the cell wall.

The pressure builds

Cell wall pushes back against the cytoplasm and cell wall resists the expansion

Expansion stop= TURGID

Question 7

What happens when the pressure potential is equal to the solute potential.

Answer 7

The water potential of the cell is zero- no more water can be drawn into a turgid cell.

Question 8

When a plant cell is turgid, what is the solute potential?

Answer 8

Zero

Question 9

Plasmolysis

Answer 9

When water leaves the cell via osmosis, the cytoplasm shrinks and pulls away from the cell wall.

Question 10

Solute potential IS

Answer 10

Water potential of solutions

Question 11

Hypertonic

Answer 11

High water potential outside

Low water potential inside

Question 12

Hypotonic

Answer 12

Low water potential outside

High water potential inside

Question 13

Isotonic

Answer 13

Equilibrium - no jet movement

Question 14

Animal cell in hypotonic solution

Answer 14

Lysis

Question 15

Plant cell in hypotonic solution

Answer 15

Cell wall prevents bursting so cell is just turgid

Question 16

Animal cell in hypertonic

Answer 16

Lose water by osmosis - crenated

Question 17

Plant cell in hypertonic solution

Answer 17

Plant cells become plasmolysed

Question 18

Define osmosis

Answer 18

The net diffusion of water molecules from a region of high water potential to a region of low water potential across a selectively permeable membrane until an equilibrium is reached.