cell fractionation

Question 1

ice - cold solution

Answer 1

prevents/reduces enzyme activity which may damage the sample

Question 2

buffered

Answer 2

solution pH = sample pH

prevents damage

Question 3

isotonic

Answer 3

solution water potential = sample water potential

prevents osmosis and osmotic damage (organelle bursting or shrivelling)

Question 4

homogenisation

Answer 4

breaking up a cell to release its organelles (e.g blending)

Question 5

filtration

Answer 5

removes debris (e.g fully intact cells)

Question 6

centrifugation

Answer 6

spinning a sample in a centrifuge
centrifuge must be balanced
separates organelles by weight (heaviest separate first/at lowest speed)

Question 7

first organelle to pellet

Answer 7

nuclei

Question 8

last organelle to pellet

Answer 8

ribosomes

Question 9

supernatant

Answer 9

the liquid left over after one organelle pellets during centrifugation

Question 10

mitochondria/chloroplast centrifuge speed

Answer 10

3500 revolutions/min

Question 11

nucleus centrifuge speed

Answer 11

1000 revolutions/min

Question 12

lysosome centrifuge speed

Answer 12

16,500 revolutions/min