A-level Biology Notes

Cell Fractionation?

-break down tissue into cells 

-add cold/isotonic /buffered solution (cold= reduce enzyme activity, buffered=maintains constant pH, isotonic= same water potential so that the organelle does not shrink or burst.)

-homogenate- breaks open cells withoit releasing organelles

-filter= removes large debris and intact cells

-centrifuge- spin at low speed, largest organelle builds at bottom (nucleus), leaves supernatant, spin at higher speed, next heaviest organelle forms at bottom (chloroplast or mitochondria)

-organelle by size: nucleus, chloroplast, mitochondria, endoplasmic reticulum/ golgi body/lysosomes, ribosome.