Cell fractionation
In order to observe a specific organelle under a microscope, you must separate them from other organelles first. This can be done through a process called cell fractionation.
- Homogenisation - the cells are broken up and the organelles are released into a solution. This solution must be ice-cold, isotonic and contain a buffer solution to maintain the pH.
- Filtration - the homogenised solution is filtered through a gauze, this separates larger debris from the organelles.
- Ultracentrifugation - The cell fragments are poured into a tube and placed into a centrifuge, then spun at a low speed. The heavier organelles form a thick sediment at the bottom of the tube - this is called a pellet. The other organelles are suspended in the fluid and this is called the supernatant..