Electron Microscope

What is the advantage of using electrons to observe a specimen instead of light? (1)

They have shorter wavelengths meaning better resolution (resolving power is greater)

What is the magnification on electron microscopes (1)

up to 500 000 x

What do electron microscopes allow us to view? (1)

Viruses and internal cell structures

What does TEM (Transmission elctron microscope) consist of doing to see these internal structures? (2)

• Cut the sample into thin sections

• Stain the sections with metal (osmium, uranium, etc) to make structures opaque to electrons which allows them to bounce off

What does an SEM (scanning electron microscope do? (1)

Sees the surface of microorganisms

What does an AFM (atomic force microscope) do and how does it do it? (2)

• used to see a molecule

• using a thin metal probe to scan a specimen revealing bumps and depressions

how small of an object can the human eye see? and examples (2)

0.2 mm (eg. adult roundworm)

how small of an object can light microscopes see and some examples? (6)

• 0.2 micrometers

• most eukaryotic cells

• nucleus

• most bacteria

• mitochondria

• prion fibril

What can an electron microscope see and some examples? (7)

• 2 nm

• everything a light microscope can

• smallest bacteria

• viruses

• ribosomes

• proteins

• lipids