Ultracentrifugation

Question 1

The filtrate is placed into a tube and the tube is placed in a centrifuge
A centrifuge is a

Answer 1

is a machine that separates materials by spinning

Question 1

The filtrate is first spun at …. speed and why

Answer 1

The filtrate is first spun at a low speed

This causes the largest, heaviest organelles (such as the nuclei) to settle at the bottom of the tube

Question 2

What are the organelles that settle at the bottom of the tube called

Answer 2

where they form a thick sediment known as a pellet

Question 3

After one of the organelles has been formed the pellet what happens to the solution

and what is it called

Answer 3

The rest of the organelles stay suspended in the solution above the pellet

This solution is known as the supernatant

Question 4

After the first spin The supernatant is ……… off and placed into another tube, which is spun at a ………. speed

Answer 4

Drained

higher

Question 5

This process of spinning the supernatant is repeated at increasing speeds until all the different types of organelle present are separated out (or

Answer 5

(or just until the desired organelle is separated out)
Each new pellet formed contains a lighter organelle than the previous pellet

Question 6

The order of the densest organelle to the least

Answer 6

Nuclei

Chloroplasts (if carrying out cell fractionation of plant tissue)

Mitochondria

Lysosomes

Endoplasmic reticulum

Ribosomes