we have learned, when
a prokaryote divides,
it duplicates its loop
of DNA and divides
into two cells.
This works for
eukaryotes are more
have their DNA in
chromosomes in a
nucleus in the
can also reproduce
division, but they
have a problem to
solve. How can
the chromosomes be
passed on so that each
new cell gets a copy
of every chromosome in
the original cell?
Eukaryotes use a
process called mitosis
for dividing one cell
into two cells.
This is how it works.
Mitosis: How the Cells
Asexual cell division is called Mitosis.
Very, very, very simply, this is how it works.
most of the time, but
carrying on the ongoing
functions of a
ATP, and keeping its
The cell is getting ready to
You can see chromosomes
in the orange colored nucleus.
The gray structures that look like lines
are the beginning of
structures called spindles.
The spindles go to opposite ends of the cell.
The spindles will pull the chromosomes
Notice that the nucleus is no longer
separate from the rest of the
The chromosomes are starting to line
up in the middle between the ends of the
spindles. The chromosomes are floating freely.
Now the chromosomes are lined up across
the middle of the cell.
They divide so that there are now two
copies of each one.
The spindles are about to pull copies
of the chromosomes to each end of the cell.
Now you can see the chromosomes being
pulled toward the poles of the spindles.
You can see that this process duplicates
and separates the chromosomes so that each new cell will be an
exact copy of the old one.
This cell is ready to reconstruct a
nucleus at each end of the cell.
The chromosomes are ready to be enclosed
in a nucleus again.
The spindles are disappearing. Their
job is done!
This cell is
becoming two identical cells.
The nuclei have formed.
The chromosomes are loosening up.
At this last stage, the cytoplasm which
fills the dividing cells is divided between them, and all the
necessary extra parts are present in each new cell.
Why is this process important to us?
Well. it is still going on in our bodies. As our hair grows,
the cells are dividing asexually. When our fingernails grow,
there is asexual division again.
When we cut our fingers and the skin
heals, the cells go through this same process.
When our bodies grow, this is how our
bones get longer and tissues grow: the cells just divide!
Header by Viau from Yellowstone
1996,1997, 1998, 1999,
2000, 2002, 2003.
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