Microscopy Flashcards
Light microscope
- Relatively cheap
- Easy to use
- Rely on light
- Any details less than 0.2pm will apear blury
- Small so easy to transport
Disadvantages of light microscope
Light microscope rely on light
Light has a much longer wavelength than electrons which means they have lower resolution than electron microscope
Meaning light microscopes have a lower maximum magnifucation
Electron microscope
- Very expensive
- Hard to use (used by scientists in labs)
- Use electrons instead of light
- maximum resolution is 0.1nm
- (2000 x better than light microscope)
- You can use them to study sub cellular structures
- Can only view dead specimen
Greater resoloution and magnification
Why do electron microscopes have greater magnification?
They use a beam of electrons rather than light waves, and the electrons have a shorter wavelength than light waves.
Resolution
Resolution means how well a microscope distinguishes between two points that are close together.
A higher resolution means that the image can be seen more clearly and more detail
What is magnification?
How many times larger the image appears compared to the real object.
Why do we add stain ?
If your specimen is completely transparent or colourless it’ll make it easier to see (different stains highlight different structures within cells)
Why do we add water on slide?
To secure the specimen in place
Equation of total magnification
total magnification = eye piece lens magnification x objective lens magnification
Equation for magnification
image size ÷ real size
What sub-cellular structures are visible through microscope
Ribosomes, Cell membrane, Xylem cells
What is the magnifiying power of an electron microscope?
2,000,000
