Modern Microscopy Flashcards
What increases microscopic sensitivity?
Fluorescence
Fluorescence
Absorb light of given wavelength (excitation wavelength)
Emit light at a different longer wavelength) emission wavelength)
Emission of light inresponse to stimulation by electromagnetic radiation
Advantages of fluorescence over conventional organic dye staining?
Can detect specific molecules in side or outside cells
Dark background increases contrast & sensitivity
Flexibility in typesof experiments
What wavelengths are longer?
Emission longer than excitation
Most important fluorescent molecule
GFP
Source of GFP
Aequorea Victoria jellyfish
Charlie,shimonura, tsein won Nobel
Cyan yellow red protein
GFP usage 1
.DNA encoding gfp can be inserted into living cells
Cells can be visualised while alive using fluorescence microscope
37°C incubator unit
GFP usage 2
DNA encoding GFP can be inserted into living animals
Shows how genesare expressed
Track genes development and disease
Trans genetic animals
Other GFP uses
Study gene expression
Where in cell proteinsare localised
Study protein activity
Changes in protein structures
Track protein movements
Cell movement
What if we want to see something smaller than light microscope?
Use illumination source with shorter wavelength means increase resolution
Beam of electrons - electron microscopy
Transmission electron microscope (TEM)
Electron beam
Travels in vacuum
Focused by magnetic coils
Passes through specially prepared specimen
Absorbed by electron dense areas of specimen which appear lighter on image..
Ruska won Nobel 86
Scanning electron microscope (SEM)
Variation of tem
3D pictures - lower resolution/ magnification
Electrons that bounce off specimen
Max knoll oatley
Scanning electron microscope (SEM)
Variation of tem
3D pictures - lower resolution/ magnification
Electrons that bounce off specimen
Max knoll oatley.
