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Prepared Slides
The easiest way to build your microscope skills
(controlling focus, light contrast, and more) is to
view prepared slides. A slide starter set is
included with your microscope. Your starter slide
set comes with five prepared slides, described
below. These descriptions get you started working
with each specimen, but you can research more
information on the internet.
Mouth Smear – Epithelial tissue is found many
places in the body – on the surface of the skin, the
lining
of
the
mouth,
stomach,
and
blood
vessels,
and
in
the
glands.
The
mouth
smear slide is squamous
epithelium taken from
the lining of the cheek.
Scan the slide on low
power (40x) and find a
group of cells that look one layer thick. You should
see very small dark spots in the middle of the cells
– these are the nuclei, which contain DNA and
control cellular functions. As you view the slide at
higher power, you will see more detail. Identify the
nucleus, the cell membrane (the wall between
cells), and the cytoplasm (the fluid inside the cell
membrane).
Pollen – When a pollen grain begins to
germinate, it grows a long, thin tube called a
pollen tube that stretches down a flower's style to
the
ovary.
The
two
sperm
in
the
pollen
grain travel through the
pollen
tube.
One
of
them then fertilizes the
egg in the ovary.
As you look at the slide
at high power (400x),
notice how thick the
walls of the pollen grains are. Locate the pollen
tubes that have grown off some of the grains.
Look for dark spots in the tubes – these are the
sperm nuclei. If there is a large dark spot in the
pollen grain, this is the "generative nucleus" that
will split to produce the two sperm.
Paramecium – A paramecium is a single-celled
protozoan that moves using cilia, tiny hairs around
its cell wall that wave back and forth. It eats by
sweeping food down an oral groove lined with cilia
into a gullet. The gullet closes off when it is full
and becomes a floating storage unit, called a food
vacuole.
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nucleus
cytoplasm
400x
400x
sperm nucleus
pollen
tube
cell wall
Page 7 of 8
Take a good look at
different
paramecia
on your slide. You
can see a large, dark
macronucleus in each
paramecium, and in
some
the
smaller
dark
micronucleus
next
to
it.
The
macronucleus
controls the metabolism of the cell (how the cell
gets energy from food) and the micronucleus
controls the cell's reproduction. With some
patience in focusing you can see the cilia at 400x
on some of the specimens. If you look closely you
may also see the oral groove – it looks like a short
depression coming in from the edge of the cell.
Housefly
Leg
Houseflies
have
tiny
hairs on their legs and
feet. They use these
hairs
for
feeling
and
tasting. Yes, they really
can taste with their feet!
As
you
look
at
the
housefly foot slide, you
won't get the whole specimen in focus at one
time. This is because it is a three-dimensional
specimen with different layers. Take a look at the
foot at low power. Notice that it has several
different joints. At higher powers you can see the
individual hairs clearly. Focus in to see where the
hair joins the foot.
Frog Blood – Frog blood looks quite different
from human blood. Human blood cells don't have
nuclei, so they are
unable to reproduce
themselves by dividing
their
DNA.
Instead,
they are made in our
bone
marrow.
Frog
blood cells do have
nuclei and thus are
able to divide.
At lowest power hundreds of tiny red blood cells
will fill your field of view. Even when magnified
only 40x, a miniscule purple dot is visible on each
cell. This dot is the nucleus. At higher power you
may find a few white blood cells – these are
different shapes than the red blood cells and
appear to be mostly a purple nucleus with only a
thin light-colored layer outside. Red blood cells
carry oxygen throughout the body, while white
blood cells work as part of the immune system.
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cilia
oral groove
macronucleus
400x
–
joint
hairs
100x
400x
nucleus
white blood cell
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