2.5.5 osmosis

Question 1

what is osmosis?

Answer 1

the movement of water from an area of high water potential to an area of low water potential

Question 2

what’s water potential?

Answer 2

a measure of the tendency of water to diffuse from one region to another
measured in kPa

Question 3

what water potential does pure water have?

Answer 3

0 kPa at standard rtp

Question 4

what water potential does water with the presence of a solute have?

Answer 4

anything below 0kPa

the more concentrated the solution the more negative the water potential

Question 5

what’s hydrostatic pressure?

Answer 5

the pressure exerted by water molecules as they collide with a membrane/container

Question 6

how does being hypotonic affect animal cells?

Answer 6

water potential is higher outside the cell which causes water to move into the cell
the hydrostatic pressure inside the cell increases which causes the cell to burst (cytolysis)

Question 7

how does being in an isotonic state affect the animal cell?

Answer 7

the water potential inside and outside the cell is equal so water enters and leaves the cell at equal rates

Question 8

how does being in a hypertonic state affect the cell?

Answer 8

water potential is higher inside the cell which causes water to move out of the cell
the hydrostatic pressure/volume of cell decreases which causes it to shrivel (crenation)

Question 9

how does being in a hypotonic state affect plant cells?

Answer 9

turger pressure increases and causes the cell to become turgid and resists the entry of further water

Question 10

how does being in a hypertonic state affect plant cells?

Answer 10

turger pressure and volume decreases and cell surface membrane is pulled away from the cell wall - making it plasmolysed