Cell Fractionation

Question 1

Definition of Cell Fractionation

Answer 1

Cell fractionation is the process used to desperate key components of the while preserving individual function of each component.

Question 2

Step 1 - Cell Fractionation

Homogenisation - Breaking up the cells.

Answer 2

Homogenisation can be fine by vibrating the cells or by grinding the cells in a blender.

This breaks the plasma membrane.

Solution must be kept ice cold in order to prevent enzymatic activity the may break down the organelles.

Solution must be kept isotonic meaning it should have the same concentration of chemicals as the cell that’s has been broken down in order to prevent the cell bursting via osmosis.

A buffer solution must be added to maintain the PH.

Question 3

Step 2 - Cell Fractionation

Filtration - Getting rid of the big bits.

Answer 3

The homogenised cell solution is filtered through a gauze to separate any large bird of cell debris or tissue debris, like connective tissue, the organelles are smaller than the debris so pass through the gauze.

Question 4

Step 3 - Cell Fractionation

Ultracentrifugation - Separating the organelles.

Answer 4

The fragments are out into a tube, then put into a centrifuge and spun at a low speed the heaviest organelle nuclei are flung to the bottom and form a thick sediment - called a pellet. The rest of the organelles stay suspended in a fluid called the supernatant.

The supernatant containing the rest of the organelles is drained off and spun at a higher speed the next largest organelle - mitochondria, will form a pellet. This prices is repeated at higher and higher speeds until all the organelles are separated.