DAT MICROSCOPY QUESTIONS AND
ANSWERS WITH SOLUTIONS 2024
Stereomicroscope (light) - ANSWER Visible light for surface of sample. Can look at living samples, but low
resolution vs compound light micro.
Compound microscope (light) - 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 - 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 - 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) - 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 - 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) - 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.
ANSWERS WITH SOLUTIONS 2024
Stereomicroscope (light) - ANSWER Visible light for surface of sample. Can look at living samples, but low
resolution vs compound light micro.
Compound microscope (light) - 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 - 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 - 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) - 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 - 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) - 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.
