2.1.1 Microscopes Flashcards
what does the word micrography mean?
a photograph taken from a microscope
What is the fundamental diffrence between magnification and resolution?
magnification is the enlargement of an image while resolution is the clearity.
How does laster scanning confocal microscopy work?
a use a laser light to scan an object point by point. built from a computer pixel by pixel
what are the pro’s and con’s of using a laser scanning microscopy?
it has high resolution. it is also depth selective so they can focus onstructures at diffrent depths in the specimen. doesn’t harm the specimen unlike election microscopes, requires a computer to assemble one image
what are the pro’s and con’s of using a TEM?
specimens need to be fixed by dehydration and staining by metal salts such as gold and platinum, this is harmful for organisms. electrons go throguh specimens meaning u can see organelles and subcellular structure unlike SEM where u can only see the cell surface membrane. the image is 2D and orginally Black and white before editing. magnification goes up to 2000000. newer ones can go up to 50000000. the resolution is 0.1nm. also not portable as its the size of a small room.
what are the pro’s and con’s of using a SEM?
these give 3D images of cells but can only see a surface membrane as the elctrons bounce off the surface meaning you can not observe organelles or subcellular componets. specimen has to be dead. speciment has to be coated in a fine film of metal which requires alot fo skill to operate. needs to be prepared in a vacume. it also not portable.
Magnification of a light microscope?
X1500
Magnification of a TEM?
X2,000,000
Magnification of a SEM?
X200,000
Resolution of a light microscope?
200nm
Resolution of a TEM?
0.1nm
Resolution of a SEM?
0.1nm
Which microscope is useful for viewing living cells?
Light (optical)
Which microscope if useful for viewing 3D images?
SEM
Which microscope is useful for viewing detailed ultrastructure of cells?
TEM
