Electron microscopes Flashcards
What are the 2 types of electron microscopes?
Transmission electron microscope and scanning electron microscope
What is a transmission electron microscope?
Electrons are transmitted through specimen, can see cell internally
What is a scanning electron microscope?
electrons hit the surface of specimen then bounce off surface, gives 3D image of the surface of cell
What are the types of preparation?
fixing, staining with heavy metals, dehydration, and embedding in resin
Why do we use preparation?
so theres a hard surface for electrons to bounce off and hit
Why are dead specimens used?
since its carried out inside a vacuum, only dead specimens used due to harsher prep needed. can cause artefacts to appear
What are artefacts?
Things created on the slide when prepping (e.g. bubbles)
Why do we dehydrate specimens?
To dry out the specimen to go into the vacuum
Why are electron microscopes better than light microscopes?
A beam of electrons is used rather than light, they have a shorter wavelength = better resolution, cell organelles visible
Why is having higher resolution + magnification important?
Means you can see cells clearer + in more detail
How are electrons microscopes different to light microscopes?
Theyre more expensive, have higher resolution + magnification, and produce black + white images
