1. KEY CONCEPT Cell cycle regulation is necessary for healthy growth.

2. Internal and external factors regulate cell division.
External factors include physical and chemical signals.
Cell to cell contact
Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells.
Growth factors are proteins that stimulate cell division.

3. Two of the most important internal factors are kinases and cyclins.
External factors trigger internal factors, which affect the cell cycle.

4. Apoptosis is programmed cell death.
a normal feature of healthy organisms
caused by a cell’s production of self-destructive enzymes
occurs in development of infants
Tadpoles to
frogs: lose
their tail
webbed fingers

5. Cell division is uncontrolled in cancer.
Cancer cells form disorganized clumps called tumors.
Benign tumors remain clustered and can be removed.
Generally considered non-cancerous
Malignant tumors metastasize, or break away, and can form more tumors.
cancer cell
bloodstream
normal cell

6. Cancer cells do not carry out necessary functions.
Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.
Don’t stick together to make tissues.

7. Carcinogens are substances known to promote cancer.
Examples: tobacco (smoking/dipping), chemicals, UV light, HPV
Standard cancer treatments typically kill both cancerous and healthy cells.

8. Mouth cancer – probably due to snuff

11. HeLa cancer cells
Named for Henrietta Lacks
She was a very poor black lady from the south in the 1940s and who died from cervical cancer in 1951
Because she was poor, uneducated, and black, she received almost no treatment for her cancer. (Which probably would have been fatal at that time anyway.)
Her cancer cells were taken from the biopsy and found to be able to grow indefinitely in labs, thus they were called “immortal.”
Researchers made millions of dollars from her cells, but her family received nothing.

12. Henrietta Lacks