4.3 Osmosis Flashcards
define osmosis:
the net movement of water from an area where it has a higher water potential to an area where it has a lower water potential through a selectively permeable membrane
what is water potential?
the tendency of water molecules to move as pressure is created by them
what is water potential measured in?
Kilopascals kPa
under standard conditions, what is the water potential?
25°C, and 100 kPa
what is water’s water potential?
0 kPa
when will water move faster?
when there’s a great difference in water potential
what does hypotonic mean?
when the solution has a lower solute concentration than inside the cell
- there’s a greater water potential outside the cell than inside
what does hypertonic mean?
when the solution has a greater solute concentration than inside the cell
- there’s a lower water potential outside the cell than inside
what does isotonic mean?
when the solution has the same solute concentration as the inside of the cell
- the water potential is the same outside and inside the cell
what happens to an animal cell in a hypotonic solution?
it’s lysed
- it absorbs the H2O and potentially bursts
what happens to an animal cell in an isotonic solution?
it’s normal
- it absorbs and secretes H2O
what happens to an animal cell in a hypertonic solution?
it’s shrivelled
- it secretes H2O
what happens to a plant cell in a hypotonic solution?
it’s turgid (normal)
- absorbs H2O
what happens to a plant cell in an isotonic solution?
it’s flaccid
-it absorbs and secretes H2O
what happens to a plant cell in a hypertonic solution?
it’s plasmolysed
- it secretes H2O
