3.1 Analysis of cell components continued

Question 1

Cell surface membrane

Function??

Answer 1

Regulates movement of substances

Question 2

Cell fractionation

Answer 2

Separates organelles

Question 3

Cell fractionation
main steps (3)

Answer 3

Homogenisation
Filtration
Ultracentrifugation

Question 4

Homogenisation

function

Answer 4

Breaking up the cells

-blender/ homogeniser

Question 5

Homogenisation

method

Answer 5

Breaks up the plasma membrane and releases the organelles into the solution

Question 6

Homogenisation

conditions

Answer 6

solution is ice cold = reduce enzyme activity = that break down organelles
solution is isotonic/ same water potential = prevent osmosis = damage/burst organelles
buffer solution added = maintain pH

Question 7

Filtration

Answer 7

Filter cell solution through a gauze
separates any large cell debris
organelles pass through gauze

Question 8

Ultracentrifugation

what

Answer 8

Separating individual organelles

Question 9

Ultracentrifugation

method

Answer 9

cell fragments into tube
tube into centrifuge
spun at low speed
heaviest organelles to bottom = thick sediment
supernatant containing rest spun faster
process repeated at higher speeds until organelles separated out