2.1, 2.2, 2.3: Microscope Types Flashcards
(14 cards)
Describe the advantages of Light Microscopes
- Cheap, easily accessible, easy to use
- Natural colour of material can be observed
- Living organisms can be observed
- Preparation is quick and simple
Describe the disadvantages of Light Microscopes
- Low resolving power
- Low magnification compared to other microscopes
Describe the advantages of Electron Microscopes in general
- Can see detail of organelles
- Better resolution and magnification than light microscopes
Describe the disadvantages of Electron Microscopes in general
- No colour
- Very large and must be operated in special rooms
- Expensive
- Damages the specimen
- Preparation of material is lengthy and complex.
Describe how a Transmission Electron Microscope works, and what type of image it produces
Fires a beam of electrons though the specimen and produces a 2D image
Describe how a Scanning Electron Microscope works and what type of image it produces
Fires a bean of electrons across the surface of a specimen and produces a 3D image.
Why do specimens need to be treated in very specific ways for Electron Microscope scanning?
Because the inside of an electron microscope is a vacuum.
For transmission electron microscopy, what has to be done to the sample?
Must be dehydrated, set in resin and stained
For scanning electron microscopy, what has to be done to the sample?
Has to be dehydrated, and coated with heavy metals.
What is a graticule?
A specialised piece of glass inserted into the microscope, that features a calibrated grid or scale etched into its surface
What are the two types of graticules?
Eyepiece graticule and stage graticule
What is the difference between a light microscope and a compound light microscope?
There is significantly less chromatic aberration and higher magnification in a compound light microscope.
What is 1 stage micrometer unit equal to?
10 micrometers
What are the names of the two lenses in a compound light microscope?
Eyepiece lens and objective lens.
