Light microscopes

Adjunto:

• Electron Microscopes

1. Advantages
   1. No vacuum
   2. Specimen can be dead or alive
   3. Low cost
      1. Good for use in schools etc.
   4. Portable
   5. Less likely to produce atifacts
   6. Natural colours seen
   7. Preparation of specimen
      1. Less harsh than for EM
   8. No technical expertise required
      1. Easy to use
2. Disadvantages
   1. Low magnification
      1. Magnification - X1500 to X2000
   2. Low resolution
   3. Can't produce 3D images
   4. Not as detailed as electron microscopes
3. Improvements to resolution
   1. Having an objective lens with a short vocal length
   2. Having a film of immersion oil between the objective lens and the specimen on the slide
4. Staining

   Nota:

   • Stains are coloured chemicals used to distinguish (highlight) specific structures.
   • The first known stain was saffron.
   1. Coloured stains
      1. Stains that bind to specific chemicals on or in the specimen allowing it to be seen
   2. Differential stains
      1. Involves more than one stain on a specimen
      2. Used for contrast