Cell Fractionation

Quick revision on cell fractionation

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Homogenisation

Breaking up the cells.

This can be done by:

-Vibrating the cells

-Grinding up the cells in a blender.

REMEMBER IN A COLD ISOTONIC BUFFER-Cold to stop enzyme action, Isotonic to prevent osmotic change & a buffer to keep the pH at a constant.

This breaks up the plasma membrane and releases the organelles...into solution.

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Filtration

GETTING RID OF THE BIG BITS.

The homogenised cell solution, is filterd through a gauze, seperate any cell or tissue debris.

Remeber: The organelles are much small so they pass through the gauze.

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Ultracentrifugation

SEPERATING THE ORGANELLES.

1- The cell fragments are poured into a test tube. The tube is put into a centrifuge (machine which spins) and is spun at a low speed. The heaviest oraganelles are flung to the bottom of the test tube by the centrifuge. Forming the pellet and the rest of the organelles are suspended in the supernatant.

2- The supernatant is drained off and poured into another tube, which is spun at a higher speed and the heavist organelles are flung to the bottom of the test tube.

This process is then repeated at higher speeds untill all the organelles are sperated.

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MINI TEST BITE

QUICK REVISION (MINI TEST)

Describe the process?

1- Homogenisation

2- Filtration

3- Ultracentrifugation

Why is an Cold isotonic buffer used?

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