Video Transcript
The micrograph provided is of the
head of an ant. Which type of microscope is most
likely to have been used to produce this image? A light microscope, a scanning
electron microscope, or a transmission electron microscope.
Let’s start by looking at the
information that we’ve been provided with by the question and the micrograph. This image is three-dimensional,
and it is showing the surface of the head of the ant. It is also in black and white. Different microscopes produce
different sorts of images, and we can use this information to determine what
microscope produced this particular micrograph.
We are using a table to compare the
three different types of microscope. Scanning electron microscopes can
be shortened to SEMs, while transmission electron microscopes can be shortened to
TEMs. Light microscopes and TEMs both produce two-dimensional, flat images, while
SEMs produce three-dimensional images. Light microscopy shows us the
natural color of specimens, which may also be stained with dyes to produce
high-contrast, colored images, while images produced by the two electron microscopes
can only be black and white, though they might have false color added later.
Light microscopes have the lowest
magnification of the three types. And therefore, they tend to be used
to view and distinguish between cells within tissues or visualize entire small
living organisms. Scanning electron microscopes have
a high magnifying and resolving power, and they work by passing electron beams over
the surface of a specimen, which are reflected by metal ions put on the specimen’s
surface. And the resulting signals are
collected by specific detectors to produce highly detailed images of the surface of
a specimen.
Transmission electron microscopes
typically have an even higher magnifying and resolving power, and they work by
passing a beam of electrons through a specimen to produce highly detailed images of
intracellular structures such as organelles.
The micrograph of the ant is in
3D. Purely based on its
three-dimensional nature, both light microscopes and transmission electron
microscopes can be ruled out, suggesting that the image was produced by a scanning
electron microscope, which does produce 3D images. The image also shows the surface of
the ant’s head. And we know that SEMs typically
produce images of the surface of specimens. The micrograph is not of the cells
themselves nor is it of intracellular structures such as organelles, so this
suggests that neither light nor transmission electron microscopes would produce this
micrograph. We can therefore deduce that this
image has been produced by a scanning electron microscope.
