Cell Fractionation

Requirements of the solution?
1. Cold- Reduce enzyme activity that might break down the ogranelles
2. Isotonic- Prevents organelles bursting or shrinking as a result of osmotic gain or loss of water.
  1. Has the same water potential as the original tissue.
3. Buffered- Maintain a constant pH.
Homogenation
1. Cells are broken up by a homogeniser to release the organelles from the cell.
2. The resultant fluid is known as the homogenate
  1. 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
1. 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
1. Process in which the homogenate is spun at a high speed to create a centrifugal force.
  1. 1) Tube of filtrate is spun at low speed.
    1. 2) Heaviest organelles, the nuclei, are forced to the bottom to form a thin sediment pellet.
      1. 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)
1. Nuclei- 1 000
  1. Mitochondria- 3 500
    1. Lysosomes- 16 500
      1. Ribosomes- 100 000

Resource summary

	Created by Olivia Farrow about 10 years ago