Cell Fractionation

• What is cell fractionation


  The process in which different parts and organelles of a cell are separated so they can be studied in detail.
• What is homogenization


  When a Homogenizer breaks open cell membranes/ walls to release organelles
• What is required of a sample to be homogenized and why?


  • Ice Cold- stop lytic enzyme activity
  • PH Buffered- To prevent damage to organelles
  • Isotonic- prevent osmotic lysis
• What is differential centrifugation and how does it work?


  Because all organelles have different densities, spinning the sample in a centrifuge allows us to separate the organelles.

  The less dense the organelles, the faster the centrifuge must spin.
• What do we do before we spin the sample


  filter to remove cellular debris so our sample doesnt end up impure
• what is the last two steps

  1. Spin Homogenate at low speed to separate a pellet of nuclei, the rest of organelles are still in the supernatent.
  2. Remove pellet and spin faster ect.
• What is the order of less dense to most dense organelles


  1. Ribosomes
  2. ER and Golgi
  3. Mitochondria and chloroplats
  4. Nuclei