DAT Microscopy Practice Study Guide
Test.
Stereomicroscope (light) - CORRECT ANSWER Visible light for surface of sample. Can look at living
samples, but low resolution vs compound light micro.
Compound microscope (light) - CORRECT ANSWER Visible light for thin section of sample. Can look at
some living samples (single cell layer). May require staining for good visibility.
Phase-contrast - CORRECT ANSWER Uses light phases and contrast. Allows for detailed observation of
living organisms (including internal structures) if thin. Good resolution/contrast, but not good for thick
samples and produces "Halo effect" around perimeter of samples.
Confocal laser scanning + fluorescence - CORRECT ANSWER Can look at thin slices while keeping sample
intact; can look at specific parts of cell via fluorescent tagging.
Can look at living cells, but only fluorescently tagged parts. Fluorescence can cause artifacts. Used to
observe chromosomes during mitosis. Note:
confocal laser scanning microscope can be w/out fluorescence as well. Uses laser light to scan dyed
specimen, then displays the image digitally.
Scanning electron microscope (SEM) - CORRECT ANSWER Look at surface of (3D) objects with high
resolution. Can't use on living: preparation is extensive (sample
needs to be dried and coated). Costly.
CryoSEM - CORRECT ANSWER Like SEM but no dehydration so you can look at samples in more "natural"
form. Can't use on living: samples frozen for prep, which can
cause artifacts.
Transmission electron microscope (TEM) - CORRECT ANSWER look at very thin cross-sections in high
detail. Can look at internal structures, very high resolution, but
can't be used on living things (preparation is extensive). Costly.
Test.
Stereomicroscope (light) - CORRECT ANSWER Visible light for surface of sample. Can look at living
samples, but low resolution vs compound light micro.
Compound microscope (light) - CORRECT ANSWER Visible light for thin section of sample. Can look at
some living samples (single cell layer). May require staining for good visibility.
Phase-contrast - CORRECT ANSWER Uses light phases and contrast. Allows for detailed observation of
living organisms (including internal structures) if thin. Good resolution/contrast, but not good for thick
samples and produces "Halo effect" around perimeter of samples.
Confocal laser scanning + fluorescence - CORRECT ANSWER Can look at thin slices while keeping sample
intact; can look at specific parts of cell via fluorescent tagging.
Can look at living cells, but only fluorescently tagged parts. Fluorescence can cause artifacts. Used to
observe chromosomes during mitosis. Note:
confocal laser scanning microscope can be w/out fluorescence as well. Uses laser light to scan dyed
specimen, then displays the image digitally.
Scanning electron microscope (SEM) - CORRECT ANSWER Look at surface of (3D) objects with high
resolution. Can't use on living: preparation is extensive (sample
needs to be dried and coated). Costly.
CryoSEM - CORRECT ANSWER Like SEM but no dehydration so you can look at samples in more "natural"
form. Can't use on living: samples frozen for prep, which can
cause artifacts.
Transmission electron microscope (TEM) - CORRECT ANSWER look at very thin cross-sections in high
detail. Can look at internal structures, very high resolution, but
can't be used on living things (preparation is extensive). Costly.
