Transcript The Cell Cycle and Cancer

The Cell Cycle and Cancer
The Stages of the Cell Cycle
1. Click on picture for cell cycle animation –
will go to www.cancerquest.org)
2. Use alt-tab keys to go between website
and power point presentation.
3. Click on blank space to proceed to next slide.)
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• SCI.9-12.B-2.7 - [Indicator] - Summarize
how cell regulation controls and
coordinates cell growth and
• division and allows cells to respond to the
environment, and recognize the
consequences of uncontrolled
• cell division.
There are several factors that regulate the
cell cycle and assure a cell divides correctly.
1.Before a cell divides,
the DNA is checked
to make sure it has
replicated correctly. (If
DNA does not copy
itself correctly, a gene
mutation occurs.
DNA replication animation:click
on DNA picture
2. Chemical Signals tell a cell when to start
and stop dividing.
(Target cells animation: click on go
sign)
3. Contact inhibition – Cells grow until they
touch each other and then they stop growing
and dividing.
(Normal contact inhibition animation: click on petri dish)
Cancer is a disease of the cell cycle. Some
of the body’s cells divide uncontrollably and
tumors form.
Tumor in Colon
Tumors in Liver
DNA mutations disrupt the cell cycle.
Mutations may be
caused by:
1. radiation
2. smoking
3. Pollutants
4. chemicals
5. viruses
While normal cells will stop dividing if there is a mutation in
the DNA, cancer cells will continue to divide with mutation.
Due to DNA mutations, cancer cells ignore
the chemical signals that start and stop the
cell cycle.
2 animations of cancer cells dividing: click on picture
•
• SCI.9-12.B-2.7 - [Indicator] - Summarize
how cell regulation controls and
coordinates cell growth and
• division and allows cells to respond to the
environment, and recognize the
consequences of uncontrolled
• cell division.
Due to DNA mutations, cancer cells cannot
communicate with neighboring cells. Cells
continue to grow and form tumors.
Skin cancer
(cancer cells dividing: click on
picture.)
SUMMARY
Normal Cell Division
1. DNA is replicated
properly.
2. Chemical signals start
and stop the cell cycle.
3. Cells communicate with
each other so they
don’t become
overcrowded.
Cancer Cells
1. Mutations occur in the
DNA when it is
replicated.
2. Chemical signals that
start and stop the cell
cycle are ignored.
3. Cells do not communicate
with each other and
tumors form.
• Benign tumours do not spread from their
site of origin, but can crowd out (squash)
surrounding cells eg brain tumour, warts.
• Malignant tumours can spread from the
original site and cause secondary
tumours. This is called metastasis. They
interfere with neighbouring cells and can
block blood vessels, the gut, glands, lungs
etc.
Metastasis – when cancer cells spread from
one part of the body to another part.
Treating Cancers
Cancer treatments include drugs that can stop
cancer cells from dividing.
• Cancer is one of the most common diseases in
the developed world:
• 1 in 4 deaths are due to cancer
• 1 in 17 deaths are due to lung cancer
• Lung cancer is the most common cancer in men
• Breast cancer is the most common cancer in
women
• There are over 100 different forms of cancer
•
• SCI.9-12.B-2.7 - [Indicator] - Summarize
how cell regulation controls and
coordinates cell growth and
• division and allows cells to respond to the
environment, and recognize the
consequences of uncontrolled
• cell division.