Cell Fractionation

Cell Fractionation:

Process of breaking down tissues/cells and separating out organelles.

Firstly, the tissue is put in a COLD, ISOTONIC and BUFFERED solution.

Cold to reduce enzyme activity that could break down the organelles.

Isotonic to prevent water movement.

Buffered to maintain a constant pH.

Then the tissue is HOMOGENISED in a HOMOGENISER which breaks down the cell. This process is HOMOGENISATION.

Usually done in a blender.

Afterwards the HOMOGENATE is filtered to remove debris.

Small organelles pass through but cell debris doesn't.

We are then left with the FILTRATE.

The filtrate is spun in an ULTRACENTRIFUGE.

This is ULTRACENTRIFUGATION.

Heavy organelles fall to the bottom (SEDIMENT).

Lighter organelles form the SUPERNATANT which is separated and spun again at a faster speed.

This process continues until you are left with the organelles you want.

Cells separated out by speed (heaviest first):

Nuclei

Mitochondria

Lysosomes

Endoplasmic Reticulum

Ribosomes