1
Q
two types of electron microscopes
A
transmission electron microscope
scanning electron microscope
2
Q
transmission electron microscope
A
- use electromagnets to focus a beam of electrons
- transmitted through a thin specimens
- denser part of specimen absorbs more electrons, so it appears darker
- produces 2D images
3
Q
resolution of electron microscope
A
very high
4
Q
scanning electron microscope
A
- scan a beam of electrons across a specimen
- bounces off the surface, and electrons are detected forming an image
- produces 3D images
- since it can scan outside surface, specimen can be thick
5
Q
scanning electron microscope resolution
A
lower
6
Q
light microscope
A
- visible light passes through the specimen
- magnification up to 1500x
- glass lenses focus the light to produce a magnified image
- produces a 2D image
7
Q
advantage of light microscope
A
- can observe live species
- affordable
- requires minimal preparation
8
Q
disadvantages of llight microscope
A
- limited magnification and resolution
- cannot view detailed organelles
9
Q
advantages of electron microscope
A
- high magnification and resolution
- detailed structures seen
- provides 3D imaging
10
Q
disadvantages of electron microscope
A
- cannot view live specimens
- expensive
- sample preparation is complex
