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Microscopy, microscopy - Coggle Diagram
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microscopy
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sample prep
dry mount
- solid specimen, sectioning
- cover slip
wet mount
- liquid
- cover slip lower at angle
squash slide
- soft samples
- wet mount but press down cover slip
smear slides
- liquid sample
- edge of slide to smear even coating
- cover slip
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electron microscope
- x500,000 magnification
- 0.5-10nm resolution
- wavelength < 1nm
- expensive and dedicated space
- complex prep = distortion
- vacuum - straight line beam
- b+w image
- dead specimen
- cell ultrastructure seen
- artefact = loss of membrane
continuity, organelle distortion,
empty space in cytoplasm
transmission electron microscope
electron beam transmitted through = image
resolving power of 0.5nm
magnification 500,000-2,000,000x
thin specimen, dener parts = darker
scanning electron microscope
beam of electrons across surface
reflected electrons collected = 3D image
resolving power 3-10nm
magnification 100,000-500,000x
mesosome artefacts
electron microscopes showed inward foldings of cell membranes after
fixation process (chemical fixing)
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cell theory
- compose all organisms
- basic unit of all life
- develop from existing cells
Light microscope
- x2000 magnification
- 200nm resolution
- 400-700nm wavelength
- cheap, portable
- simple prep and no damage
- natural colour / stain
- living or dead specimen
- eyepiece and objective lens
- lit from underneath
- artefact = bubbles
staining = increase contrast
as components take up stain to different degrees
- +ve dye = negative components
- -ve dye repelled by cytosol = cell unstained
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atomic force microscopy
- cantilever and laser beam
- brush surface - laser deflections detected
- viewed in normal cell conditions
- 0.1nm resolution (atomic level and bonds)
- help understand how drugs interact