The document discusses the normal cell cycle and how cancer disrupts it. In the normal cell cycle, DNA replication is checked carefully. Chemical signals tell cells when to divide and neighboring cells communicate to prevent overcrowding. In cancer, mutations in DNA replication cause cells to ignore signals and crowd together to form tumors. Causes of DNA mutations include radiation, smoking, pollution and viruses. Cancer treatments target the unchecked cell division caused by these mutations.

1. The Cell Cycle and Cancer

2. 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.

3. 2. Chemical Signals tell a cell
when to start and stop dividing.
(Target cells animation: click on go
sign)

4. Neighboring cells communicate with
dividing cells to regulate their growth also.
(Normal contact inhibition animation: click on petri dish)

5. Cancer is a disease of the cell cycle.
Some of the body’s cells divide
uncontrollably and tumors form.
Tumors in Liver
Tumor in Colon

6. DNA mutations disrupt the cell
cycle.
Mutations may be
caused by:
1. radiation
2. smoking
3. Pollutants
4. chemicals
5. viruses

7. While normal cells will stop dividing if there
is a mutation in the DNA, cancer cells will
continue to divide with mutation.

8. 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

9. 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.)

10. HOMEWORK
 HOMEWORK:
 What ARE THE 5 MOST COMMON CANCERS IN BOLIVIA?
 Explain one natural treatment for cancer
 Written by hand

11. 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.

12. Treating Cancers
Cancer treatments include drugs that can stop
cancer cells from dividing.