1. ELECTRON MICROSCOPY

2. LIMITATIONS OF THE LIGHT MICROSCOPE Light microscopes rely on visible light being refracted to magnify the image. Scientists were unable to study organelles without the invention of a new, higher powered microscope.

3. Was invented in the 1950s. THE ELECTRON MICROSCOPE

4. Rather than light, an electron microscope focuses a beam of electrons onto or through the specimen. Modern electron microscopes are capable of obtaining resolutions up to 100 times that of standard light microscopes.

5. THE ELECTRON MICROSCOPE Electron microscopes come in 2 varieties: Scanning electron microscopes (SEM) Transmission electron microscopes (TEM) Both are used in Biology for today, but for different purposes.

6. SCANNING ELECTRON MICROSCOPES Are used to to study the topography, or outside surface of the specimen. In an SEM, the electron beam scans the surface of the specimen

7. SEM image of a midge (a small fly) SCANNING ELECTRON MICROSCOPE

8. TRANSMISSION ELECTRON MICROSCOPES (TEM) Are used to study the internal structure of cells TEM aim an electron beam through a very thin section of the specimen, similar to the way a light microscope transmits light through a slide.

9. TRANSMISSION ELECTRON MICROSCOPES (TEM)

10. ROUGH ENDOPLASMIC RETICULUM

11. http://images.wellcome.ac.uk/ Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Spot the difference?

12. The ‘spots’ are the difference! The Rough Endoplasmic Reticulum is peppered with ribosomes that give it the rough appearance It is where protein synthesis occurs

13. GOLGI APPARATUS

14. PLANT CELL VACUOLE

15. MITOCHONDRIA

16. CHLOROPLASTS