water potential

Question 1

Why do water molecules move from less concentrate solutions to more concentrated ones?

Answer 1

forces of attraction between water molecules and solute molecules are stronger

Question 2

what makes a solute osmotically active?

Answer 2

if there are forces of attraction between them and the water molecules

Question 3

give examples of osmotically active molecules?

Answer 3

polar molecules and ions

Question 4

how can isotonic solutions be used medically?

Answer 4

intravenous fluids and donor organ transportations

Question 5

why must intravenous fluids be isotonic?

Answer 5

when delivering: nutrition and medication - prevent movement of water in or out of cells

Question 6

why must donor organs be stored in isotonic solutions be isotonic?

Answer 6

prevent cell damage

Question 7

what is water potential?

Answer 7

potential energy of water per unit volume, relative to pure water at 20 degrees Celsius

Question 8

what two things affect water potential in living things?

Answer 8

• solute concentration
• hydrostatic pressure

Question 9

how does solute concentration affect water potential?

Answer 9

when solute dissolves, energy is reduced, lowering the water potential - more viscous

Question 10

how does hydrostatic pressure affect water potential?

Answer 10

increasing pressure increases potential energy, increasing water potential

Question 11

what is the equation for water potential?

Answer 11

solute potential + pressure potential

Question 12

what happens when you bathe a plant cell in a hypertonic solution?

Answer 12

• higher solute conc bathing sol
• higher water pot. in cell
• plasmolysed cell

Question 13

what happens when you bathe a plant cell in a hypotonic solution?

Answer 13

• lower solute conc bathing sol
• lower water pot. in cell
• turgid cell