3.8 - Electron Microscopes Flashcards
How a transmission electron microscope works How a scanning electron microscope works The differences between light and electron microscopes
What do electron microscopes use to form an image?
Electrons
Why do electron microscopes have better resolution than light microscopes?
Electrons have a shorter wavelength
Are electron microscopes more or less expensive than light microscopes?
More expensive
What color are images produced by electron microscopes?
Black and white
What are the two types of electron microscopes?
Transmission electron microscope (TEM) and Scanning electron microscope (SEM)
What are artefacts in microscopy?
Visible details that aren’t part of the specimen
How do TEMs form an image?
By transmitting a beam of electrons through a specimen
What do denser parts of a specimen do in a TEM?
Absorb more electrons
What type of structures can TEMs be used to observe?
Internal structures of organelles
What type of specimens can be observed with a TEM?
Non-living or dead organisms
What is the maximum resolution of a TEM?
Around 0.5 nm
What is the maximum magnification of a TEM?
Around x 1
How do SEMs form an image?
By scanning a beam of electrons across the surface of a specimen
What type of images do SEMs produce?
3D images of the surface
What type of specimens can be observed with a SEM?
Non-living or dead specimens
What is the maximum resolution of a SEM?
Around 5 nm
What is the maximum magnification of a SEM?
Around x 1
What is the maximum magnification of a light microscope?
x 1
What is the maximum resolution of a light microscope?
0.2 µm
What type of sample preparation is required for a light microscope?
Simple
What type of image is produced by a light microscope?
2D
What type of specimens can be used with a light microscope?
Living or dead
