3.1 methods of studying cells Flashcards
magnification definition
how many times larger an object looks under a microscope
resolution definition
minimum distance apart that two objects can appear as 2 separate items
size of eukaryotic cell
1-20 micrometres
size of bacterial cell
0.1-5 micrometres
cell fractionation
isolating organelles so their structures and functions can be studied
what is homogenisation
breaking open a cell using a blender and cold isotonic, buffered solution
solution is then filtered to remove large cell debris
why should the solution be cold
to reduce enzyme activity so organelles aren’t damaged
why should the solution be isotonic
to keep the same water potential so organelles don’t shrivel/burst
why should the solution be buffered
to keep a constant pH to remove large cells
what is ultracentrifugation
filtered solution is spun at different speeds in a centrifuge and organelles separate according the densities
order of organelles (starting with lowest speed)
nuclei
chloroplast
mitochondria
lysosomes
endoplasmic reticulum
ribosome
what is the pellet
the organelle left (as it has the heaviest density, forming at the bottom)
what is the supernatant
fluid at the top of the tube (which is then taken and re spun at a higher speed)
