Cell Fractionation Flashcards
(9 cards)
Define cell fractionation.
The process where cells are broken up (lyses) and the different organelles within the cell are separated out.
What is the tissue placed in before cell fractionation can begin?
- A cold, buffered solution with the same water potential as the tissue.
Why is the isolation medium in cell fractionation a **cold*, buffered solution with the same water potential as the tissue?
- Cold to keep Enzyme activity low and prevent hydrolytic enzymes damaging organelles.
- Buffered to keep the pH stable to all the organelles and their enzymes to function properly.
- The same water potential to make upsurge that water does not energ or leave the organelles by osmosis, so they don’t swell or shrink and get damaged.
What are the three steps of cell fractionation called?
- Homogenization
- Filtration
- Ultracentrifugation
Describe the homegenization stage of cell fractionation.
- This breaks open the cells, usually done by either vibrating the cells or grinding them up in a homogeniser (blender).
- This releases organelles from the cells.
Describe the filtration stage of cell fractionation.
- The resulting fluid (homogenate) is filtered to remove any debris (whole cells or large bits of remaining tissue).
Describe the ultracentrifugation stage of cell fractionation.
The fragments in the filtered homogenate are separated in a centrifuge at increasing speeds.
What is the supernatant?
- Smaller and less dense components.
- Used if performing repeated centrifugation.
What is the pellet?
- Larger and more dense components.
- Removed before repeated centrifugal ion.