Cell Fractionation

Question 1

What is the first step of cell fractionation?

Answer 1

1. Cells are broken up using a homogeniser, breaking the cell membrane and releasing the organelles

Question 2

What is the second step of cell fractionation?

Answer 2

2. Filter off any cell debris leaving a suspension

Question 3

What is the third step of cell fractionation?

Answer 3

3. The suspension is then centrifuged at a low speed

Question 4

How would you separate the organelles?

Answer 4

The most dense organelle, the nucleus, separates first into a pellet. The lasting supernatant is then poured into a fresh tube and is spun at higher speeds

Question 5

In what order do the organelles separate?

Answer 5

1. Nucleus
   (1.5. Chloroplasts)
2. Mitochondria
3. Ribosomes

Question 6

Why is a cold solution used?

Answer 6

Because the enzyme activity is reduced and it prevents the digestion of organelles

Question 7

What is an isotonic solution?

Answer 7

A solution with the same water potential, or same concentration, which prevents osmotic lysis and the organelle crenating

Question 8

Why is the solution buffered?

Answer 8

To keep the pH levels in the solution constant preventing denaturisation of enzymes and proteins