Cell Fractionation

Question 1

Why would you need to use cell fractionation ?

Answer 1

To view organelles under electron microscope.

Cell fractionation separates them from rest of cell sample

Question 2

First step in cell fractional

Answer 2

Homogenisation - breaking up cells

Question 3

How can homogenisation be done ?

Answer 3

Vibrating or grinding cells up in blender.

Question 4

Why do cells need to be grinded up?

Answer 4

Break plasma

Cause organelles to release into solution

Question 5

Name 3 things the solution must be / need ?

Answer 5

ICe Cold
Isotonic
Buffer added

Question 6

Why ice cold ??

Answer 6

Reduce enzyme activity

Question 7

Why isotonic ??

Answer 7

Same concentration of chemicals as the cells being broke down to prevent damage to organelles through osmosis.

Question 8

Why buffer added ??

Answer 8

Maintain pH.

Question 9

Second step in cell fractionation .

Answer 9

Filtration - getting rid of big bits

Question 10

Why is homogenised solution filtered?

Answer 10

Through a gauze to separate large cell debris like connective tissue

Question 11

Why is a gauze used ?

Answer 11

As organelles are much smaller than Debris so pass through gauze .

Question 12

Third step in cell fractionation

Answer 12

Ultracentrifugation- separating organelles

Question 13

Cell fragments are poured into a tube. Where does this go?

Answer 13

Centrifuge and spun at low speed.

Question 14

What comes our first from centrifuge ?

Answer 14

Heaviest organelles like nuclei.

Flung to borrow of tube.

Question 15

What do the organelles form at bottom of tube ?

Answer 15

Thick sediment at bottom called the pellet.

Rest of organelles stay suspended in fluid above - supernatant

Question 16

Supernantant is drained off and poured into another tube. What happens next?

Answer 16

Spun in centrifuge at higher speed.

Heaviest organelles form pellet at bottom of tube .

Question 17

The process repeats…

Answer 17

At higher and higher speeds until all organelles are separated out l.

Question 18

So what happens to the pellet ?

Answer 18

It’s made up of lighter and lighter organelles

Question 19

What is the order in mass of organelles from heaviest to lightest?

Answer 19

Nuclei 
(Chloroplast)
Mitochondria 
Lysosomes
ER
Ribosomes

Question 20

What is the acronym to remember the Order of organelles?

Answer 20

Naughty clever monkeys like eating red raspberries.