methods of studying cells

Question 1

optical microscope

Answer 1

-light radiation
-low cost
-basic training
-staining required
-live specimens
-true colour
-low magnification
-low resolutions
-2D

Question 2

TEM

Answer 2

-electron radiation
-expensive
-extensive training
-staining required
-dead specimens
-black and white
-high magnification
-high resolution
-vacuum required
-2D

Question 3

SEM

Answer 3

-electron radiation
-expensive
-extensive training
-staining required
-dead specimen
-black and white
-high magnification
high resolution
-vacuum required
-3D

Question 4

cell fractionation

Answer 4

-tissue chopped up and homogenised in an ice cold isotonic buffer solution
-mixture filtered to remove debris
-spun in ultra centrifuge, first at low speed
-spinning increases gravitational field and the organelles separate according to density
-gradually gets faster

Question 5

cell fractionation stages

Answer 5

-pellet 1, whole cells and nuclei
-pellet 2, chloroplasts and mitochondria
-pellet 3, lysosomes, ER, other vesicles
-pellet 4, ribosomes and viruses

Question 6

ice cold

Answer 6

-reduces enzyme activating that might break up organelles

Question 7

isotonic

Answer 7

-to prevent organelles from bursting or shrinking

Question 8

buffer

Answer 8

-to maintain a constant pH