Microscopy 2.1.1

Question 1

Transmission electron microscope (TEM)

Answer 1

• uses electromagnets to fire a beam of electrons
• Internal structures are seen
• Can only see thin specimens
• Can only view dead specimens
• Artefacts can be produced
• No colour
• high resolution (0.5nm)
• x500,000 magnification
• only produces 2D image

Question 2

Scanning electron microscope (SEM)

Answer 2

• scan a beam of electrons across a specimen
• produce 3D specimens
• shows surface (external structure) of specimen
• used on thick specimens
• lower resolution (3-10nm)
• cannot observe live specimen
• do not produce coloured image
• 500,000x magnification

Question 3

Compound light microscope

Answer 3

• focused by lenses
• low resolution (200nm)
• x2000 magnification
• can view live and dead specimen
• artefacts can be produced
• produces coloured image
• produces 2D image

Question 4

Laser scanning confocal microscope

Answer 4

• focused by lenses
• laser is shone to make a single point of light
• lower resolution (200nm)
• x2000-10,000 magnification
• produces 3D and 2D Images
• live or dead specimen
• thin or thick specimen
• can produce coloured images