1. Regulation of the Cell Cycle
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EQ: What happens if the cell cycle isn’t controlled?

2. The Cell Cycle is regulated
Cells take cues from internal & external factors to decide whether or not to divide
This ensures that cells don’t divide under unfavorable conditions (DNA is damaged or not enough room, etc.)

3. The Cell Cycle is regulated
Checkpoints
G1: Checks for cell size, nutrients, growth factors, DNA damage
If it doesn’t have the right signals, cell can go back to G0
G2: Checks for DNA damage, makes sure DNA was replicated properly
If there are mistakes, cell tries to fix them; if mistakes can’t be fixed cell will undergo apoptosis
Spindle checkpoint: Checks that chromosomes are correctly attached to spindle during metaphase

4. Apoptosis Programmed cell death A normal feature of healthy organisms
webbed fingers
Programmed cell death
A normal feature of healthy organisms
Caused by a cell’s production enzymes designed to destroy the cell

5. Cell Cycle Regulation Problems
If something goes wrong in the cell cycle, A disease can occur One example is cancer. OTHER DISEASES CAN BE CAUSED BY CELL CYCLE ERRORS

6. Cell Cycle Regulation Problems
2 Types of tumors:
Benign: remain clustered and can be removed
Malignant: metastasize (spread) to different areas of the body and can form more tumors; cancer is this type of tumor
cancer cell
bloodstream
normal cell

7. Cell Cycle Regulation Problems: Cancer
Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.
Genes are damaged by things called carcinogens
Carcinogens – things known to cause cancer
(ex: UV rays, cigarette smoke, pollution, alcohol, asbestos, etc.)
Cancer cells do not receive the signals telling the cell to not divide, so they divide constantly
Cancer is uncontrolled cell division
Cancer cells do not carry out normal cell functions

8. Cell Cycle Regulation Problems: Cancer
Treatments for cancer kill cancer cells & healthy cells