Cell Fractionation

The process of separating different parts and organelles of a cell, so that it can be studied in greater detail. The most common method is differential centrifugation. 

This is where the organelles are separated due to their different densities. 

There are three key stages: 

1. Homogenisation 
2. FIltration 
3. Centrifugation 

Homogenisation: 

Pestle and mortar or a blender to break open the cells. You will need and ice cold, isotonic buffer solution:  

• COLD: This reduced enzyme activity and will reduce autolysis (self destruction) of the organelle. 
• ISOTONIC: To prevent osmotic movement where swelling of organelle may cause lysis or shrinkage of the organelle, both processes will result in the destruction of its natural function. 
• BUFFER SOLUTION: Preventing any change of pH, which may damage the organelles, either by denaturing the enzymes or the proteins affecting its function. 

Filtration: 

This is to remove any debris (unbroken cells, cartilage etc). This will prevent contamination of the pellets resulting from the centrifugation. 

Centrifugation: 

Homogenate is centrifuge at different speeds, The speed and length of centrifugation will increase each time. The densest organelle sinks to the bottom, and the remaining solution, the supernatant, is separated for further centrifugation. 

Naughty Monkeys Like Eating Raspberries 

• Nuclei 
• Mitochondria 
• Lysosomes 
• ER 
• Ribosomes