Transcript Cancer and the Cell Cycle

CANCER AND THE CELL CYCLE
Mrs. Gamari
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No matter how many new homes a builder builds,
even if building the same design, the builder and
the crew rely on the blueprint instructions for
their construction.
Similarly, cells rely on instructions for going
through the cell cycle.
NORMAL CELL DIVISION
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Growth should balance
(apoptosis) old cell death
CHECKPOINTS
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Cyclins –
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proteins that bind to enzymes (cyclin-dependent
kinases) in the stages of interphase and mitosis to
start various activities of the cell cycle.
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Different cyclin/CDK combinations control different
activities
Start of the cell cycle
 DNA replication
 Protein synthesis
 Nuclear division
 End of the cell cycle
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CELL GROWTH
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Epithelial layers of skin
Basal layer cells should
balance outer surface cells
CANCER
Uncontrolled growth and division of cells
 Results when cell cycle checkpoints fail
 Cancerous cells can kill an organism by crowding
out normal cells, impairing normal tissue
function.
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TUMOR FORMATION
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Cancer cells lack
“contact-inhibition”
Basal cell layer
outnumbers cells in
surrounding areas.
WHY MIGHT THE CHECKPOINTS FAIL?
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Cells can become “abnormal” in a variety of ways.
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Carcinogens = cancer-causing substances
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Toxins / Chemicals
UV Radiation
Could be influenced by genes OR environment
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Diet/Lifestyle
Viruses
Family history
ALL OF THESE SOMEHOW DAMAGE THE PART OF DNA
THAT REGULATES CELL DIVISION
WHAT IS A MUTATION?
GENES THAT HELP REGULATE CELL
DIVISION
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Tumor Suppressor Genes
DAMAGE
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Proto-oncogenes
DAMAGE
DIFFERENTIATION
CANCER CELL CHARACTERISTICS
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Cancer cells are usually
irregularly shaped.
Cancer cells are more
simplistic or
undifferentiated.
HEALTHY CELL FUNCTIONS
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Make proteins or “worker molecules” required by the
body
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Communicate with other cells by sending signals and
messages
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Make their own energy using oxygen
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Divide to make new cells
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Grow in a controlled fashion and know where they
belong in the body
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Die after a specific number of divisions (apoptosis)
CANCER CELL FUNCTIONS
(OR LACK THEREOF)
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Proteins can be missing, misshaped or in unnecessary
amounts
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Messages or signals used for communication are missing or
changed
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Energy is made using sugar (usually just glycolysis- not
aerobic respiration)
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Growth is not regulated so the cancer cells grow out of
control (dysplasia).
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Cells can go places in the body where they do not belong
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An “immortal” nature allows the cancer cells to live longer
than normal
GOOD CELLS GONE BAD!
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Each group provided with a “normal cell” and a
“cancer cell”.
Examine the contents of the cells and determine
what each object symbolizes.
Fill out worksheet and answer analysis
questions.