Biology – Day 30 Friday November 23, 2012
Osmosis – movement of H O acr2ss a semi-permeable membrane
- H 2 moves from a region of higher come (H O) to 2 lower concentration (of H O) 2
a. Higher soluble concentration inside a cell vs. outside (hypertonic concentration).
H 2 moves into a cell because H O i2 higher in concentration outside of the cell.
b. Lower solution concentration inside cell vs. outside (hypotonic concentration)
H 2 moves out of the cell because H O is2in higher concentration inside the cell.
c. Equal concentration of solute inside vs. outside (isotonic)
- No net movement of H O 2
- Can quantify it by applying enough pressure to reverse the flow of H O into2the cell.
- Osmotic Potential will have:
o A) Value of either – or O
o A more negative Osmotic Potential has a greater potential to take up H O.
- Pressure exerted in cytoplasmic membrane against the cell wall Turgor Pressure
- Turgor Pressure is high when the cell membrane pressed against the cell wall
- If the cell membrane is not pressed against the cell wall – plasmolysis occurs.
Wp = Op + Pp
(Water Potential = Osmotic Potential + Pressure Pote