3 3.1 Cell Fractionation

Question 1

What are the 3 stages?

Answer 1

Homogenisation, Filtration and Ultracentrifugation

Question 2

What is homogenisation?

Answer 2

Breaking up the cell

Question 3

What conditions must be met for homogenisation?

Answer 3

An isotonic solution ( the same concentration of water as the cell to prevent osmosis)
A cold temp to reduce enzyme activity
A maintained ph achieved with a buffer solution

Question 4

What is the blended solution called?

Answer 4

The homogenate

Question 5

Why is filtration essential?

Answer 5

So large debris are removed

Question 6

What is the point of Cell Fractionation?

Answer 6

To prepare organelles to be looked at under a microscope

Question 7

How does Ultracentrifugation work?

Answer 7

The organelles are spun in a tube in a centrifuge and the heaviest organelles will fall to the bottom to form a pellet whilst the lighter ones stay suspended above in the supernatant

Question 8

What is the point in increasing the speed after draining the supernatant?

Answer 8

The lighter organelles will fall to the bottom with increased speed

Question 9

What is the order of weight in cell organelles?

Answer 9

Biggest—————————————————————Smallest
Nuclei Mitochondria/Chloroplast Lysosome S/RER Ribosome