Function - Light (compound microscope)
Uses visible light to illuminate a thin section of sample.
Function - Confocal laser scanning microscope
Let’s you look at thin ‘slices’ in a sample while keeping it intact; let’s you look at specific parts of a cell (such as individual proteins) by labelling them with fluorescence.
Function - Scanning Electron Microscope
Lets you look at the surface of objects at high resolution.
Function - Transmission Electron Microscope
Lets you look at a very thing cross-section of an object (such as a cell)
Disadvantages - Light (compound microscope)
• Low resolution compared to Electron Microscope.
Disadvantages - Confocal laser scanning microscope.
- low resolution comp to Electron
- sees only fluorescent objects, nothing else visible.
- fluorescent can cause artefacts
Disadvantages - Scanning Electron Microscope
- Resolution often not as high as TEM.
- can’t look at living samples (they much be dried and covered in metal).
- expensive to run.
Disadvantages - Transmission Electron Microscope.
- can’t be used on living things (samples much be prepped extensively beforehand).
- costly to run.
Useful for looking at - Compund Microscope (light)
- living things (single cell layer).
- cells & tissues (prep is less critical).
- getting an overview.
Useful for - Confocal laser scanning microscope.
- looking a living cells.
- understanding cell relationships.
- highlighting individual components.
Useful for - SEM
- looking at surfaces of objects.
* looking at objects in 3D.
Useful for - TEM
- looking at internal structures of objects.
- looking at objects at very high resolution.
- looking at relationships between structures at high resolution.
The compound microscope shines light through what part of a sample?
A slice of a living sample.
What example can be used to explain how the Confocal technique works?
If the cell is a pancake stack, each pancake can be viewed to build a 3D model.
When using SEM, what gets knocked off by the surface of the sample then picked up by the detector?
Secondary electrons.
What’s the TEM’s main advantage?
Very high resolution.
