1. Regulation of the Cell Cycle

2. Regulating Division
Division is regulated by physical and chemical factors.
Physical: cells stop dividing when they touch other cells.
p53: protein that blocks cell division if the DNA is damaged. Mutation in this protein often causes cancer.

3. Apoptosis Programmed cell death.
caused by production of destructive enzymes
occurs in development of infants.

4. Cancer: Good Cells Gone Bad
Uncontrolled cell growth
May divide quickly and indefinitely
Occurs when the genes involved in cell-cycle regulation are damaged.
Cells do not carry out necessary functions, often damage healthy tissue.

5. What Causes Cancer? Carcinogens: agents known to cause cancer.
Ex: gasoline, cigarettes
Radiation
Random genetic mutations

6. Cancer Terms
Benign tumors grow slowly and are encapsulated (can be removed easily).
Malignant tumors are invasive, grow fast, and often metastasize.
Metastasis: cancer cells move from one organ or tissue to another.

7. Curing Cancer
Radiation and chemo kill all dividing cells (including healthy cells)
How chemo drugs work
Some work by stopping DNA replication
Some inhibit spindle fiber formation (= no mitosis)
Some stop blood vessel formation to tumor (no blood = tumor dies).

8. The real reason dinosaurs became extinct