Microscopy Flashcards
What is magnification and what is it controlled by?
By how much an image is enlarged under a microscope.
It is controlled by the power of the lenses used
What is resolution and what is it controlled by?
The minimum distance between two objects at which a microscope can distinguish them as separate entities.
It is controlled by wavelength of the illumination used
What are the three types of microscope?
Light microscope, transmission and scanning electron microscopes
What are the benefits of TEMs?
- high magnification
- high resolution (shorter wavelength)
- produces 2D photomicrograph
- focuses using condenser electromagnet
What are the limitations of TEMs?
- can’t look at living cells
- must be in a vacuum (sealed edges)
- has to be thin
- complicated prep. (may have artefacts e.g dust)
- does not produce colour img
What are the benefits of SEMs?
- high magnification
- specimen doesn’t have to be thin
- focuses using condenser electromagnet
- produces 3D img using computer analysis
What are the limitations of SEMs?
- can’t look at living cells
- must be in a vacuum
- complicated prep. (may have artefacts)
- does not produce a colour img
What are the benefits of light microscopes?
- live specimens can be used
- real colour can be seen
What are the limitations of light microscopes?
Its resolution and magnification is lower than EMs
How many micrometres in 1 mm?
1 000
How many nanometres in 1 mm?
1 000 000
What is the formula for magnification?
img size/actual size
