methods of studying cells - 2 Flashcards
topic 2
magnification formula
magnification= size of image/size of real object
define resolution
how detailed the image is
magnification definition
how much bigger the image is than the specimen
2 types of electron microscopes
transmission and scanning
2 types of microscopes
optical and electron
maximum resolution of optical microscopes
0.2 micrometers
maximum magnification of optical microscope
x1500
maximum resolution of electron microscope
0.0002 micrometers
maximum magnification of electron microscope
x1,500,000
TEMs advantages
high resolution images, shows small images
TEMs disadvantages
can only be used on thin specimens
non-living specimens
SEMs advantages
3D
used on thick specimens
SEMs disadvantages
gives lower resolution
only used on non-living specimens
4 steps of preparing a microscope slide
- pipet small drop of water in the centre of the slide
- tweezers place thin section of specimen on top of water drop
- add a drop of stain
- add a cover slip
3 main stages of cell fractionation
homogenisation
filtration
ultracentrifugation