4.3 Osmosis Flashcards
Define osmosis.
the passage of water from an area of higher water potential to an area of lower water potential, through a semi-permeable membrane
What is water potential represented by (symbol) and what is it measured in?
psi (Ψ) and kiloPascals (kPa)
What is the greatest possible water potential, and how does it change when a solute is added to a solution?
0Ψ (pure water), and the addition of a solute will lower the water potential, decreasing it into the negatives (e.g. -0.2Ψ)
What happens when an animal cell is placed in a HYPOTONIC solution?
water enters the cell via osmosis, and the cell bursts (cytolysis)
hypotonic- lower solute conc., higher water potential than body fluids
What happens when an animal cell is placed in a HYPERTONIC solution?
water exits the cell via osmosis, and the cell shrivels (plasmolysis)
hypertonic- higher solute conc., lower water potential than body fluids
What happens when an animal cell is placed in an ISOTONIC solution?
the cell will stay as it is, as there will be no net movement of water
isotonic- same solute conc. and water potential as body fluids
What happens when a plant cell is placed in a HYPOTONIC solution?
water enters the cell via osmosis, and the cell swells and becomes turgid. cytolysis (bursting) is prevented by the presence of the cell wall.
hypotonic- lower solute conc., higher water potential than plant cell
What happens when a plant cell is placed in a HYPERTONIC solution?
water exits the cell via osmosis, and the protoplast (cell membrane and contents) shrivels, pulling away from the cell wall (plasmolysis)
hypertonic- higher solute conc., lower water potential than plant cell
What happens when a plant cell is placed in an ISOTONIC solution?
the cell will reach a stage where the protoplast (cell membrane and contents) no longer presses on the cell wall (incipient plasmolysis)
isotonic- same solute conc. and water potential as plant cell
