Lesson 5: Water Potential

Question 1

Water Potential

Answer 1

There is always a net movement of water from hypotonic to hypertonic solution because there is a higher concentration of water molecules in the hypotonic solution
-when solutions are isotonic the water diffusing in one direction is exactly offset by that moving in the other direction (there is no net movement of water)

Question 2

Red Blood Cells

Answer 2

-red blood cells contain a variety of solutes dissolved in their cytoplasm
-if placed in pure water it will absorb water and will burst in haemolysis
-if a red blood cell is placed in a solution with lower water potential water will leave the cell and it will shrink (crenated)

Question 3

Plant Cells

Answer 3

-plants contain a variety of solutes
-when placed in pure water they will absorb the water
-plant cells are bathed in almost pure water
-the protoplasm will swell which will push against the cell wall
-pressure potential builds up on the cell and no more steer can enter so the pressure potential increases increasing the water potential of the cell ( turgid cell)

Question 4

Plant cells 2

Answer 4

-if a plant is placed in a solution with lower water potential than its own water leaves
-the volume of the cell decreases and so does the pressure potential
-a stage is reached where the protoplasm doesn’t touch the cell wall the fire the pressure potential is 0 (incipient plasmolysis)
-further loss of water of water will cause the cell to shrink further (plasmolysis)