2.3.4: Osmosis

Question 1

define osmosis

Answer 1

the net movement of free water molecules down a water potential gradient through a semi-permeable membrane until an equilibrium is reached

Question 2

what is the main difference between diffusion and osmosis?

Answer 2

diffusion doesn’t have to be across a membrane whereas osmosis must be across a membrane

Question 3

what is water potential

Answer 3

the tendency of free water molecules move into/out of a solution/cell

Question 4

is water potential a quantitative or qualitative measurment?

Answer 4

quantitative

Question 5

what is water potential measured in

Answer 5

kPa- kilopascals

Question 6

what is the highest water potential possibel and what substance has this water potential

Answer 6

pure water - 0 kPa

Question 7

define the term hypertonic

Answer 7

the water potential of the external solution is lower than the cell - hyper = high solute therefore low water potential

Question 8

define the term hypotonic

Answer 8

the water potential of the external solution is higher than the cell

Question 9

define the term isotonic

Answer 9

the water potential of the external solution is the same as the cell

Question 10

what does adding solutes to water do to its water potential

Answer 10

lowers the water potential as there are fewer free water molecules

Question 11

what effect does adding solutes do to the water potential of a solution

Answer 11

makes it more negative

Question 12

what happens to a plant cell in a solution that is hypotonic

Answer 12

water enters cell = turgid

Question 13

what happens to a plant cell in a solution that is hypertonic

Answer 13

water leaves cell = plasmolysis

Question 14

what happens to an animal cell in a solution that is hypotonic

Answer 14

water enters cell = cell lysis

Question 15

what happens to an animal cell in a solution that is hypertonic

Answer 15

water leaves cell = crenates