Transcript Osmosis - A level biology

Osmosis
Osmosis is the net movement of water
molecules over a partially permeable
membrane from an area of less osmotic
potential to an area of more negative osmotic
potential.
Water potential
Water potential is a measure of water molecule potential for movement
in a solution. Water always moves by osmosis from less negative to
more negative water potential. The highest possible water potential
is that of pure water which is 0, all other solutions have a negative
water potential. Water potential is measured in Pa.
Hypertonic Solutions
Hypertonic solutions contain a high
concentration of solute relative to another
solution for example the cells cytoplasm.
Water diffuses out of a cell when it is
placed in isotonic solution which causes
the cell to shrivel.
Hypotonic Solutions
Hypotonic Solutions have a high
concentration of solute relative to a
different solution i.e. the cells cytoplasm.
Water diffuses into the cell when it is
placed in a hypotonic solution, this means
the cell swells and possibly explode.
Isotonic solutions
Isotonic solution has the same concentration
as another solution for example the cells
cytoplasm. Water diffuses in and out of
the cell at the same rate when placed in
an isotonic solution. The fluid surrounding
body cells is isotonic.