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1-5
1. What chemicals regulate the cell cycle? How do they work?
The chemicals that regulate the cell cycle are cyclins. Cyclins regulate the timing of the cell cycle in eukaryotic cells.

2. What happens when cells do not respond to the signals that normally regulate their growth?
Cancer cells do not respond to the signals that regulate the growth of most cells. Because of that, they form lots of cells called tumors that can damage the tissues that are surrounding the cancer cells.

3. How do cells respond to contact with other cells?
Cells respond with contact to other cells by making their neighboring cells to stop or slow down their cell cycle.

4. Why can cancer be considered a disease of the cell cycle?
Cancer can be considered a disease of the cell cycle because they have a defect in a gene which normally stops the cell cycle until all chromosomes have been properly copied.

5. Critical Thinking:
If cyclin was injected into a cell that was in mitosis then would cause a mitotic spindle to form because it seems to regulate the cell cycle.