3. Exchange across Cell Membranes: Osmosis

Question 1

define osmosis

Answer 1

osmosis is the movement of molecules from an area of higher water potential, to lower water potential, across a partially permeable membrane

Question 2

define water potential

Answer 2

it is the potential of water molecules to diffuse out or into a solution

Question 3

what solution has the highest water potential?

Answer 3

pure water, anything else has a lower water potential

Question 4

what does isotonic mean?

Answer 4

when two solutions have the same water potential

Question 5

what does the rate of osmosis depend on?

Answer 5

• the water potential gradient: the higher the water potential gradient, the faster the rate of osmosis
• the thickness of the exchange surface: the thinner the exchange surface, the faster the rate of osmosis
• the SA of exchange surface: the highe the SA , the faster the osmosis

Question 6

how can you make solutions of different concentrations?

Answer 6

by using a scale factor