Cellular transport – Osmosis
In class practical – Osmosis in Eggs Practical & Validation
Questions
Investigating osmosis and cell membranes from observing the effects of
different concentrations
Understanding and using appropriate terminology to describe the
movement of water molecules across the selectively permeable cell
membrane
Background Information:
There have been many different models of the cell membrane
proposed to explain observations of cells in different
environments and results of investigations. Cell membranes are
too thin to observe them directly, but it is possible to infer cell
membrane structures from the reactions to different materials
and different conditions.
Terminology:
Tonicity is the relativeconcentration ofsolutes dissolved in solution
which determine the direction and extent ofdiffusion across a selectively
permeable membrane. It is commonly used when describing the response
ofcells immersed in an external solution. (Intracellular fluid and
extracellular fluid)
Tonicity Description Diagram explaining
osmotic flow
Hypertonic A hypertonic solution
has a greater
concentration
ofsolutes than
another solution.
Hypotonic A hypotonic solution
has a lower
concentration of
solutes than another
solution.
