CANCER AND THE CELL CYCLEMrs. Gamari

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

Growth should balance (apoptosis) old cell death

CHECKPOINTS

Cyclins – proteins that bind to enzymes (cyclin-dependent

kinases) in the stages of interphase and mitosis to start various activities of the cell cycle.

Different cyclin/CDK combinations control different activities Start of the cell cycle DNA replication Protein synthesis Nuclear division End of the cell cycle

CELL GROWTH

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.

TUMOR FORMATION

Cancer cells lack “contact-inhibition”

Basal cell layer outnumbers cells in surrounding areas.

WHY MIGHT THE CHECKPOINTS FAIL? Cells can become “abnormal” in a variety of

ways.

Carcinogens = cancer-causing substances Toxins / Chemicals UV Radiation

Could be influenced by genes OR environment 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

Tumor Suppressor Genes

Proto-oncogenes

DAMAGE

DAMAGE

DIFFERENTIATION

CANCER CELL CHARACTERISTICS

Cancer cells are usually irregularly shaped.

Cancer cells are more simplistic or undifferentiated.

HEALTHY CELL FUNCTIONS Make proteins or “worker molecules” required by

the body

Communicate with other cells by sending signals and messages

Make their own energy using oxygen

Divide to make new cells

Grow in a controlled fashion and know where they belong in the body

Die after a specific number of divisions (apoptosis)

CANCER CELL FUNCTIONS (OR LACK THEREOF) Proteins can be missing, misshaped or in unnecessary

amounts

Messages or signals used for communication are missing or changed

Energy is made using sugar (usually just glycolysis- not aerobic respiration)

Growth is not regulated so the cancer cells grow out of control (dysplasia).

Cells can go places in the body where they do not belong

An “immortal” nature allows the cancer cells to live longer than normal

GOOD CELLS GONE BAD!

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.