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Microbiology Lab Midterm - Critical Thinking Questions and answers
already passed 2025
1. Week One: Microscopy:
Assume the diameter of the field
of vision in your microscope is 2
mm under low power. If one Bacil-
lus cell measures 2 μm long, how
many Bacillus cells could fit end
to end across the field? How
many 10 μm yeast cells could fit
across the field?
2. Name two ways in which you can
enhance the resolving power
3. What are the advantages of the
low-power objective over the oil
immersion objective for viewing
fungi or algae?
4. What would occur if water were
accidentally used in place of im-
mersion oil?
5. Why are microorganisms hard to
see in wet preparations?
6. Can you distinguish the prokary-
There
are
1,000
um
in
a
mm.
So
there
are
2,000
um
in
the field,
Therefore:
1000
Bacillus
would
fit
in
the
viewing
field
(2000um/2um). and 200 yeast
(2000/10).
Two
ways
in
which
you
can
enhance
the
resolving
power is
by
switching
to
a
higher
aperture
lens
or
by
decreasing
the amount of light being used.
The advantages of the low-power objective over the
oil
immersion objective for viewing fungi or algae are that
it
helps you to get a better view of the fungi or algae
since
they are larger organisms.
What would occur if water were accidentally used in place
of immersion oil is that the image would not be clear.
Microorganisms are hard to see in wet preparations
be- cause they move around quickly and since they
aren't stained we are unable to see the contrast of
