Download Station 1: Cork cells

Station 1: Cork cells
In 1665, Robert Hooke used an early compound microscope to look at a thin slice of cork.
Under the microscope, the cork seemed to made of thousands tiny, empty chambers. Hooke called
these chambers “cells” because they reminded him of a monastery’s tiny rooms, which were called
cells. Cork is made from wood and was at one time living, although it is no longer considered alive
when it is in cork form. As you know, all living things are made of cells and this wood is no
exception. The cells are square- shaped and have a rigid outer wall (the cell wall, found in plant
cells). It is the remains of the cell walls that you are seeing, which make the small box shapes.
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Station 2: Cheek cells
The internal parts of the cells, the organelles, are so transparent (clear) that they are often
difficult to see. Biologists have developed a number of stains that help them see the cells and their
organelles by adding color to their transparent parts. These cells have been stained with methylene
blue stain. This stain sticks particularly well to DNA so you should be able to see the nucleus of the
cells. The other organelles and parts are too small and not stained properly to see. These cells are
thin with interlocking edges so that they can form a flexible barrier inside your mouth. This is just
one way that cheek cells have structure related to their functions of protection and barrier.
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Station 3: Bacteria shapes (spiral)
Most bacteria come in three shapes: spherical, rod, and spiral. Can you tell which type these
bacteria are? These are spiral-shaped bacteria and are generally the largest of the three common
shapes. Streptococcus spp. (species) are chain-forming, sphere-shaped bacteria responsible for
ailments such as strep throat in humans. Remember that bacteria are prokaryotes and are generally
much smaller than plant and animal cells (eukaryotic cells). Can you see a difference in their size?
Below is a picture showing the three shapes of bacteria.
Sphere shaped
Spiral Shaped
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Rod shaped
Bacteria capsules
This slide shows several bacteria that have capsules. Remember that bacteria are generally
simple structures. The bacterial cell lacks a membrane-bound nucleus. Because of this, bacteria are
described as prokaryotes. Bacteria are normally unicellular organisms that grow in colonies with
other bacteria. Some bacteria are enclosed within a capsule – a hard protective coating
surrounding the cell wall and membrane. This protects the bacteria. Bacteria may also have cilia
and flagella to help them move in their environment. Do you remember what these look like?
.
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flagella
Station 4: Plant leaf
This is a leaf from the aquatic plant growing in our classroom. This cell has lots of
chloroplast because it is responsible for making the food for the entire plant. Like any complex cell,
it has the basic organelles. You will not see the nucleus and the DNA in this lab, but the cell wall
and chloroplasts will be very obvious. The chloroplasts are the site for photosynthesis in the cell;
they contain chlorophyll (a green pigment), which traps sunlight and thus enables the cell to combine
carbon dioxide and water to make glucose. This is the process where plants take inorganic carbon
dioxide and use the sun’s energy to make carbohydrates.
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Station 5: Muscle cell – smooth muscle
This is a muscle cell. Remember that muscle is a tissue made up of several cells all working
together. Muscle cells can come in three types: heart muscle, smooth muscle, and skeletal muscle.
This is an example of smooth muscle. Smooth muscle is made of single, string-shaped cells. Each
smooth muscle cell contains thick (myosin) and thin (actin) filaments that slide against each other to
produce a contraction in the cell. The nucleus in these cells are pushed off to the side and can be
seen as the darker spots between the pink colored cells. These muscles help move blood in your
body and help food move through your digestive system. The cells are long and thin shaped so that
they can slide past each other to provide movement. This structure or shape is responsible for how
the cells function and the job that they do. We cannot see the other organelles like mitochondria but
we know that muscle cells need a lot of energy and probably have lots of mitochondria.
Mitochondria are the organelles that provide the cell with energy.
Label the cell membrane and nucleus in this tissue. Remember that you are seeing a lot of cells
together but each cell has its own nucleus and membrane.
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Station 6: Euglena
Euglena are unicellular organisms that have a nucleus. They are in the kingdom Protista because of
this.
All euglena have chloroplasts and can make their own food by photosynthesis. On these slides we
cannot see the chloroplasts because the cells have been died pink.
Euglena move by a flagellum (plural ‚ flagella), which is a long whip-like structure that acts like a
little motor. The flagellum is located on the anterior (front) end, and twirls in such a way as to pull
the cell through the water. If you look closely at some of the Euglena cells you may be able to see
the flagellum
Euglena also have an eyespot at the anterior end that detects light, it can be seen near the reservoir.
This helps the euglena find bright areas to gather sunlight to make their food.
In the center of the cell is the nucleus, which contains the cell's DNA and controls the cell's
activities. The dye used to prepare this slide colors the DNA a darker pink color than the rest of the
cell. Make sure to look for this dark spon inside the cell.
On your drawing label the cell membrane and nucleus.
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