Electron Microscope

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In transmission EM the electrons pass through the specimen

Specimen needs to be extremely thin - 10nm to 100nm

TEM can magnify objects up to 500 000 times

TEM has made it possible to see the details of and discover new organelles - see page 9 in Collins

Slide 10

Transmission Electron Microscope (TEM)

Cells or tissues are killed and chemically ‘fixed’ in a complicated and harsh treatment (in full detail in table 3.1 pg 52 Rowland)

How does this differ to light microscopy?

This treatment can result in alterations to the cell - known as artefacts

What will this mean for the images produced?

Slide 11

Transmission Electron Microscope (TEM)

Transmission electron micrograph of epithelial cells from a rat small intestine.

Scale bar = 5 mm.

Slide 12

Scanning Electron Microscope (SEM)

In Scanning EM microscopes the electrons bounce off the surface of the specimen

Produce images with a three-dimensional appearance

Allow detailed study of surfaces

Slide 13

Scanning Electron Microscope (SEM)

Now watch the following clip explaining SEM

Slide 14

Scanning Electron Microscope (SEM)

Slide 15

Links

www.learn.co.uk/

www.microscopy-uk.org.uk/intro/index.html

www.mwrn.com/feature/education.asp

http://www.feic.com/support/tem/transmis.htm

http://anka.livstek.lth.se:2080/microscopy/foodmicr.htm

Slide 16

Light & Electron Microscopes

Copy & complete the following table