Cell Fractionation

Question 1

What is cell fractionation?

Answer 1

A process that separates organelles based on size, allowing them to be studied under an SEM or TEM

Question 2

What is homogenisation?

Answer 2

• tissue sample must be homogenised to break apart cells
• sample must be kept in specific conditions:
  cold: reduces enzyme activity that may damage organelles
  isotonic: prevents osmosis that could shrink or burst organelles
  buffer solution: keeps pH constant and avoids damaging protein structures

Question 3

What is filtration?

Answer 3

tissue sample is filtered to remove any large debris

Question 4

What is ultracentrifugation?

Answer 4

• homogenate is spun at a low speed in a centrifuge
• the largest organelles (e.g nucleus) form at the bottom and create a pellet
• pellet is removed and supernatant (remaining liquid) is spun again at a higher speed
• this removes the next largest organelles
• this process is repeated until the desired organelle is removed