3.1 Cell fractionation

Question 1

cell fractionation:

Answer 1

the process where cells are broken up and the different organelles they contain are separated out

Question 2

what is done before cell fractionation:

Answer 2

the tissue is placed in a cold, buffered, isotonic solution

Question 3

why does the solution have to be cold, buffered and isotonic

Answer 3

cold - reduces enzyme activity that could break down the organelles
buffered - pH doesn’t fluctuate, prevents the altering of the structure of organelles or the function of enzymes
isotonic - stops the organelles from bursting or shrinking as a result of osmotic gain or loss of water

Question 4

homogenation:

Answer 4

cells broken up by a homogeniser (blender)
- releases organelles from the cell

Question 5

why is the homogenate filtered?

Answer 5

removes any complete cells and large pieces of debris

Question 6

ultracentrifugation process:

Answer 6

• homogenate placed in a test tube
• spun at low speed
• heaviest organelles forms a pellet at the bottom of the test tube
  -supernatant (fluid at the top) is removed and placed in another test tube
  (process repeated at higher speeds to remove the next heaviest organelle)