Download The Cell Cycle and Cancer

The Cell Cycle and Cancer
•
The Stages of the Cell Cycle
There are several factors that regulate the
cell cycle and assure a cell divides correctly.
1.Before a cell divides,
the DNA is replicated
in S phase, and
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 programmed into the
DNA tell a cell when to start and stop
dividing.
(Target cells animation: click on go
sign)
3. Neighboring cells communicate with
dividing cells to regulate their growth also.
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 that occur in S phase disrupt
the cell cycle when DNA is damaged or not
copied correctly.
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.
https://www.youtube.com/watch?v=IeUANx
FVXKc
Due to DNA mutations, cancer cells cannot
communicate with neighboring cells. Cells
continue to grow and form tumors.
Skin cancer
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.
Treating Cancers
Currently, most cancers are treated by either
removing the tumor (biopsy), or trying to kill
the cancer cells through:
• Radiation Therapy
• Chemotherapy
(Unfortunately, these treatments
are not specific to cancer cells.
They also kill healthy cells,
causing the patient to lose hair,
become nauseous, and become
extremely weak.)