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ZOOLOGY LAB
B
MODULE 3
Introduction:
The cell is universally considered to be
'alive' and being such, it performs
fundamental
life
functions
and
processes. Cells 'eat', 'digest', 'excrete',
communicate, reproduce, adapt to their
environment, move, or change shape.
One basic example of process performed
at the cellular level is osmosis.
Osmosis is the diffusion of water through
a semipermeable membrane based on
the concentration gradient of water
across the membrane.
-
Diffusion of water across a
differentially
selectively
permeable membrane due to
concentration differences.
-
Whereas
diffusion
transports
material across membranes and
within cells, osmosis transports
only water across a membrane
and the membrane
mbrane limits the
diffusion of solutes in the water.
-
Osmosis is a special case of
diffusion. In animal cells, the
classic demonstration of osmosis
and osmotic pressure is to
immerse the cells in solutions of
varying osmolarity and watch
what
happens
under
the
compound
microscope.
This
laboratory
exercise
will
demonstrate this perspective.