OSMOSIS
AND
DIFFUSION
By
Chonell Peralta
and
Rosa Parra
WHAT IS OSMOSIS AND DIFFUSION?
• Osmosis is the
movement of water
across a membrane in
response to a solute
concentration
gradient.
• Diffusion is the
movement of
molecules from an
area of higher
concentration to an
area of lower
concentration.
WHY IS OSMOSIS AND DIFFUSION IMPORTANT?
• Adults have approx.
60% water
• 42 L
• Intracellular fluid =28L
• Interstitial fluid = 11 L
• Plasma = 3L
• Water is the solvent for all
living matter
TONICITY
• Tonicity pertains to a
solution and how it
affects cell volume
• Hypertonic = solution
makes cell shrink
• Hypotonic = solution
makes cell swell
• Isotonic = cell does
not change (optimal
solution)
SURFACE AREA TO VOLUME RATIO
• Efficiency of a cell is based on its size
RATE OF DIFFUSION
• Nonpolar
molecules
diffuse rapidly
• Ions use
protein
channels
• Polar
molecules use
facilitated
diffusion
PASSIVE TRANSPORT
• No energy is used for
osmosis to occur
• Osmosis occurs by
facilitated diffusion
• Protein channel is needed
for diffusion to take place
• Aquaporins are used to
diffuse water in and out
of the cell