Microscopes

Uses light

low resolution - max.=0.2 micometres

Mostly used for whole cells or tissues

Maximum magnification is x1500

Laser scanning confocal microscopes

Uses laser beams to scan specimen tagged with fluorescent dye

Laser fluresces dye to give light

Light is focussed by a pinhole onto a detector which is hooked to a computer to make a 3D image

Pinhole focusees the light

Used to look at different depths in thick specimens

Use electrons

Higher resolution so more detailed

Transmission electron microscope (TEM)

electromagnets focus a beam of electrons to the specimen

Denser parts have more electrons.

High resolution

Only used on thin specimens

Scanning electron microscope (SEM)

beam of electrons scanned across specimen

Knocks off electrons from the specimen which gather in cathode ray tube forming an image

Image shows surface of specimen and can be 3D.

Lower resoltuion that TEMs