osmosis

Question 1

what are the units for water potential

Answer 1

kilo pascals (kPa)

Question 2

outline the term water potential

Answer 2

measure of the tendency of water molecules to diffuse from one region to another

Question 3

is osmosis an active or passive process

Answer 3

passive

Question 4

why does the visking tube increase in size

Answer 4

• the visking tube’s external surface acts as a partially permeable membrane
• the solution in the visking tube has a lower water potential (more negative) then the surrounding solution
• water diffuses in via osmosis through the partially permeable membrane of the visking tube

Question 5

why do plants become turgid

Answer 5

• Plant placed in a solution that has a higher water potential compared to plant cells (hypotonic)
• Water diffuses into plant cells via osmosis through a partially permeable membrane.
• The water diffuses into the vacuole, the vacuole expands exerts turgor pressure causing membrane to expand against the cell wall
• The plant cell becomes turgid

Question 6

Why would a plant cell be less likely to not burst when placed in distilled water?

Answer 6

it has a cell wall to resist the pressure exerted by the water and the pressure of the expanding cell membrane

Question 7

why would a red blood cell eventually burst in distilled water

Answer 7

• A red blood cell does not have a cell wall
• water moves in by osmosis from a high water potential to a low water potential
• The influx of water produces a higher pressure - (hydrostatic pressure)
• the cell membrane expands but can not resist the increasing pressure of the water.

Question 8

What is an isotonic solution

Answer 8

• 2 solutions separated by a partially permeable membrane have the same water potential.
  There is no net movement of water particles into either solution.
• the movement of water into the cell is equal to the movement of water out of the potato cells

Question 9

What is a hypotonic solution

Answer 9

• A hypotonic solution has a lower solute concentration, therefore a higher water potential compared to another solution
• water would move into the cell as the cell has a low water potential

Question 10

What is a hypertonic solution

Answer 10

• A hypertonic solution contains a higher concentration of solutes, it has a lower water potential compared to another solution.
• water would move out of the cell into the solution by osmosis as the cell has a higher water potential

Question 11

describe the process of osmosis

Answer 11

Movement of water particles from a high water potential to a low water potential, down a water potential gradient through a partially permeable membrane