water potential

Question 1

What is water potential?

Is it positive or negative?

Answer 1

The measure used to determine whether water will move in one direction or another and the overall pressure on water
Both

Question 2

What is water potential measured in?

Answer 2

Pascals (Pa) or kilopascals (kPa)

Question 3

What is the rule regarding water potential?

Answer 3

Water always falls from high to low water potential

Question 4

How is water potential abbreviated?

Answer 4

Using the Greek letter psi (Ψ)

Question 5

What 2 components is water potential made up of?

Answer 5

Pressure potential (Ψp) and solute potential (Ψs)

Question 6

What is pressure potential?

Answer 6

Hydrostatic pressure due to an external force

Question 7

If pressure potential is positive what kind of force is exerted?

Answer 7

A compression force

Question 8

If pressure potential is negative what kind of force is exerted?

Answer 8

A tension force

Question 9

What is pressure potential also known as in plant cells?

Answer 9

Turgor pressure

Question 10

What is solute potential?

Answer 10

Pressure due to dissolved solutes

Question 11

How does the concentration affect solute potential?

Answer 11

The higher the concentration, the lower the solute potential

Question 12

Why is solute pressure always negative?

Answer 12

Because pure water has a solute potential of zero therefore any solute will decrease the solute potential

Question 13

What is solute potential also known as?

Answer 13

Osmotic potential

Question 14

What are the three different solutions that allow us to understand the water potential of cells?
(3 things)

Answer 14

1. A hypotonic solution
2. A hypertonic solution
   3, An isotonic solution

Question 15

What is a hypotonic solution?

Answer 15

A solution with a lower solute concentration, or higher water potential, than the cell

Question 16

What is a hypertonic solution?

Answer 16

A solution with a higher solute concentration, or lower water potential, than the cell

Question 17

What is an isotonic solution?

Answer 17

A solution with the same solute concentration and water potential as the cell

Question 18

Why, in animal cells, is water potential almost always zero?

Answer 18

Because animal cells don’t have cell walls and therefore there is rarely an external force acting on them

Question 19

What happens to animal cells in a hypotonic solution?

Answer 19

Th animal cell will burst as when water enters the cell membrane it won’t be able to resist pressure

Question 20

What happens to animal cells in a hypertonic solution?

Answer 20

The animal cell will shrink because water will leave the cell

Question 21

What will happen to an animal cell in an isotonic solution?

Answer 21

Water will diffuse equally in both directions so the cell size will stay the same

Question 22

Why is the water potential in a plant cell almost always positive?

Answer 22

As plant cells have cell walls and the cell walls are strong, they can apply external force to the cell

Question 23

What happens to the plant cell in a hypotonic solution?

Answer 23

The plant cell will swell until it reaches a dynamic equilibrium when positive pressure potential exactly balances the negative solute potential so the overall water potential is zero and there is no net movement of water. This means that the cell is turgid.

Question 24

What happens to a plant cell in an isotonic solution?

Answer 24

The water potential equals zero and therefore the cells are flaccid as they don’t take in or give out water.

Question 25

What happens to the plant cell in a hypertonic solution?

Answer 25

The plant cell will undergo plasmolysis which is where the membrane shrinks and pulls away from the cell wall because water leave the cell and the cytoplasm shrinks