Cold- Reduce enzyme activity
that might break down the
ogranelles
Isotonic- Prevents
organelles bursting or
shrinking as a result of
osmotic gain or loss of
water.
Has the same water potential as
the original tissue.
Buffered-
Maintain a
constant pH.
Homogenation
Cells are broken up by a
homogeniser to release the
organelles from the cell.
The resultant fluid
is known as the
homogenate
This is filtered
to remove and
complete cells
and large
pieces of debris
Process
where cells
are broken up
and the
different
organelles
separated out
The techniques of cell fractionation and
ultracentrifugation enables considerable
advances in biological knowledge. They
allowed a detailed study of the structure
and function of organelles.
ULTRACENTRIFUGATION
Process in which
the homogenate is
spun at a high
speed to create a
centrifugal force.
1) Tube of filtrate is spun at low speed.
2) Heaviest organelles, the nuclei, are
forced to the bottom to form a thin
sediment pellet.
3) Supernatant is removed, leaving the sediment of nuclei.
4) Supernatant is transferred to another tube, and
spun in the centrifuge at a faster speed.
~PROCESS IS REPEATED~
Order of separation of organelles
(and speed of centrifugation)