Cell Fractionation

Question 1

What conditions are needed for cell fractionation?

Answer 1

• Cold. To reduce enzyme activity that might break down the organelles.
• Is of the same water potential as the tissue - to prevent organelles bursting or shrinking as a result of osmotic gain or loss of water.
• Buffered - so that the pH doesn’t fluctuate. Any change in the pH could alter the structure of the organelles or affect the functioning of enzymes.

Question 2

Homogenisation

Answer 2

Cells are broken up by a homogeniser.
This releases the organelles from the cell.
The resultant fluid (homogenate) is then filtered to remove and complete cells and large pieces of debris.

Question 3

Ultracentrifugation

Answer 3

A method of separating the contents of a homogenised fluid of cells.

Question 4

Order of contents of ultracentrifugation

Answer 4

Nuclei
Mitochondria
Lysosomes