11 MZB II - Faresse

s.B.

• Magnification is the number of times an image's size is enlarged.
• Resolution is a measurement of how well the smallest details of an image can be discerned.

Object that’s less than half the wavelength of the microscope’s illumination source is not visible under that microscope.

Light microscopes use visible light which has a minimum wavelength of 400 nm
-> This means that we will never be able to see any object smaller than approximately 200 nm using a light microscope

The wavelength of electrons is thousand of times shorter than visible light (0.4 nm).
-> This means that we will be able to see objects of approximately 0.2 nm using an EM.

3 elements are required:
- A bright light focused onto the specimen by a condenser.
- A specimen thin enough to allow light to pass through it.
- An appropriate set of lenses to focus the image in our eye.

1. Fixation
- Stop all biochemical reactions
- Preserves tissues from decay
- Generally with Aldehydes PFA or GA
2. Dehydration Embedding
- To prepare embedding
- Baths of alcohol to remove the water
- Bath of Xylol to remove alcohol
3. Embedding
- To harden the tissue
- Immersion in melted, paraffin, resin, or plastic
- Hard after cooling, easier to cut
4. Sectioning
- Using a Microtome
- Light microscope (210 µm)
- Electron microscope (40-100 nm)
5. Staining
- Rehydration using a baths of diluted alcohols
- Immersion in staining solutions

Immunostaining is a general term in biochemistry that applies to any use of an antibody-based method to detect a specific protein in a sample

Fluorochrome, Fluoreszenzfarbstoffe, Moleküle, die in der Lage sind, eingestrahlte Energie in Form von Fluoreszenzlicht (Fluoreszenz) wieder abzugeben
-> Licht mit einer bestimmten Wellenlänge wird Absoriert und anschliessend wird licht mit einer anderen bestimmten Wellenlänge abgegeben

Filter 1: allows only wavelengths that excite the fluorochrome
Filter 2: allows only the light emitted by the fluorochrome