Cell fractionation

• Cell fractionation is where a cells organelles are separated from the cell to be studied.
• STEP 1:

  1.       The cell tissue is stored in a cold, buffered isotonic solution to prevent any damage to the organelles.

  ·         Low temperature slows enzyme activity to prevent anything being broken down, the buffer maintains pH to stop proteins denaturing and an isotonic solution prevents shrinkage.
• STEP 2:

  2. The cells are broken up by a homogeniser (blender) to physically break up the cells.
• STEP 3:

  3. The broken-up cells are then placed in an ultracentrifuge. This separates out the cell organelles according to their different weights.

  • The heaviest organelles end up at the base of the test tube and are removed. This process is repeated, and the second heaviest organelles are removed.
• STEP 4:

  This process is continued until all of the cell components are separated out according to weight.
• An ultracentrifuge is used to separate the released contents based on density.
• A homogenizer is used to mechanically disrupt the cells so that they release their contents into the surrounding medium.
• Different types of centrifuges can be used depending on what needs to be isolated
• A centrifugal force is applied which causes the heavy particles to move towards the bottom of the container while lighter ones remain nearer the top.
• Centrifugation allows us to isolate specific parts of a cell or tissue sample by taking advantage of differences in size, shape, and density between them.