Techniques in Cell Biology Flashcards
What is the optical resolution limit?
The minimal distance that allows recognition of object details
What allows better resolution in a microscope?
A smaller wavelength of light/beam
What is the wavelength of visible light?
390-700nm
What is the wavelength of an electron beam?
0.0025nm
What is the advantage of light microscopy?
Cells are alive
What is the disadvantage of light microscopy?
Low resolution
What is the advantage of electron microscopy?
High resolution
What is the disadvantage of electron microscopy?
Cells are dead
What is advanced electron microscopy used for?
Single molecule analysis
What does a scanning electron microscope focus on?
A sample’s surface and composition
What does a transmission electron microscope focus on?
The details of a sample’s internal composition
What is fluorescence?
The emission of light by a substance that has absorbed light
Is light emitted from a fluorescent molecule at a shorter or longer wavelength than the wavelength of light at absorption?
Longer
In basic terms, how does a fluorescence microscope work?
It excites the specimen and collects the emission light
What does fluorescence microscopy allow for visualisation of?
Visualisation of single molecules
What is the origin of Green Fluorescent Protein?
From the jellyfish Aequorea victoria
Who is credited with the discovery of Green Fluorescent Protein?
Osamu Shimomura
What was Martin Chalfie awarded a Nobel Prize for?
The discovery that GFP can be used to tag proteins.
What colour light is used to allow for emission by proteins tagged with GFP?
Blue light
What does FRAP stand for?
Fluorescent Recovery After Photobleaching
What does FLIP stand for?
Fluorescent Loss In Photobleaching
What is FRAP used for?
Revealing differences in membrane fluidity and protein mobility.
What is FLIP used for?
To examine the movement of molecules in cells and membranes.
What is photoactivation?
Fluorescent proteins that become visible after laser radiation
