Page | 1
BIOL 200 - UNIT 1:
MICROSCOPY 2026 LATEST
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Resolution and Electron Microscopy - correct answer --
Electrons have shorter wavelengths than light
*Pros*: good resolution at size range important for cell studies
*Cons*: samples must withstand electron bombardment and
vacuum, so elaborate specimen prep is req'd (fixation, resin
embedding, sectioning to slices 50-100nm)
- Since organic material is made primarily of carbon, heavy metal
stains must be used to increase contrast.
- AKA cells must be dead
Scanning electron microscopy (SEM) - correct answer -- The
specimen is usually dried and coated with a very thin layer of gold
or some other heavy metal
, Page | 2
- The electron beam is scanned across the surface of the
specimen in a series of lines.
- As the beam of electrons hits the specimen, secondary electrons
are ejected from the surface of the specimen. These are collected
by a secondary electron detector that electronically builds an
image based on electron intensity (from white to black).
*This technique produces images of surfaces only.*
- The magnification obtained overlaps the light microscope and
TEM ranges
- Black background with white specimen
*Pros*: great for surfaces, 3-D images
(the surface could also refer to an internal surface of your sample,
if you first freeze the sample and break it open)
*Cons*: requires a vacuum so most specimens have to be fixed
and dried (aka deeeed).
Questions to consider when determining what type of microscopy
is being used - correct answer -What is the magnification/ scale
of the image?
Does it look 3-dimensional? Is there depth to the image?
Is there a black background? Does the sample look like its
emitting the particles used for imaging?
BIOL 200 - UNIT 1:
MICROSCOPY 2026 LATEST
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Resolution and Electron Microscopy - correct answer --
Electrons have shorter wavelengths than light
*Pros*: good resolution at size range important for cell studies
*Cons*: samples must withstand electron bombardment and
vacuum, so elaborate specimen prep is req'd (fixation, resin
embedding, sectioning to slices 50-100nm)
- Since organic material is made primarily of carbon, heavy metal
stains must be used to increase contrast.
- AKA cells must be dead
Scanning electron microscopy (SEM) - correct answer -- The
specimen is usually dried and coated with a very thin layer of gold
or some other heavy metal
, Page | 2
- The electron beam is scanned across the surface of the
specimen in a series of lines.
- As the beam of electrons hits the specimen, secondary electrons
are ejected from the surface of the specimen. These are collected
by a secondary electron detector that electronically builds an
image based on electron intensity (from white to black).
*This technique produces images of surfaces only.*
- The magnification obtained overlaps the light microscope and
TEM ranges
- Black background with white specimen
*Pros*: great for surfaces, 3-D images
(the surface could also refer to an internal surface of your sample,
if you first freeze the sample and break it open)
*Cons*: requires a vacuum so most specimens have to be fixed
and dried (aka deeeed).
Questions to consider when determining what type of microscopy
is being used - correct answer -What is the magnification/ scale
of the image?
Does it look 3-dimensional? Is there depth to the image?
Is there a black background? Does the sample look like its
emitting the particles used for imaging?
