Cell Fractionation Flashcards
(9 cards)
1
Q
Define cell fractionation.
A
The process where cells are broken up (lyses) and the different organelles within the cell are separated out.
2
Q
What is the tissue placed in before cell fractionation can begin?
A
- A cold, buffered solution with the same water potential as the tissue.
3
Q
Why is the isolation medium in cell fractionation a **cold*, buffered solution with the same water potential as the tissue?
A
- 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.
4
Q
What are the three steps of cell fractionation called?
A
- Homogenization
- Filtration
- Ultracentrifugation
5
Q
Describe the homegenization stage of cell fractionation.
A
- 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.
6
Q
Describe the filtration stage of cell fractionation.
A
- The resulting fluid (homogenate) is filtered to remove any debris (whole cells or large bits of remaining tissue).
7
Q
Describe the ultracentrifugation stage of cell fractionation.
A
The fragments in the filtered homogenate are separated in a centrifuge at increasing speeds.
8
Q
What is the supernatant?
A
- Smaller and less dense components.
- Used if performing repeated centrifugation.
9
Q
What is the pellet?
A
- Larger and more dense components.
- Removed before repeated centrifugal ion.
