1. 10-3 Regulating the Cell Cycle Reading: 250-253 Homework Sheet: 10-3

2. Different Cells Grow and Divide at Different Rates Most nerve and muscle cells stop growing and dividing. In contrast, skin, bone and blood cells continue to grow and divide throughout life.

3. Cyclins Regulates the Cell Cycle Cyclins- proteins found in eukaryotic cells that regulate cell division.

4. Cyclins Regulate the Cell Cycle Both Internally vs. Externally Internal Regulators- proteins found inside the cell that regulate the cell cycle. External Regulators- proteins found outside the cell that regulate the cell cycle.

5. What Happens When Cell Growth Cannot Be Controlled? Cancer cells do not respond to the signals that regulate the growth of most cells. Tumor- a mass of cancer cells.

6. Stem Cells are Undifferentiated Stem cells- come from early embryonic development, and can give rise to many different types of tissues in the body.