9.3 Cell Cycle Regulation Normal Cell Cycle Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Normal Cell Cycle Different chemical signals start and stop the phases of the cell cycle.

If a cell is not needed, it dies Apoptosis: Programmed cell death Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation If a cell is not needed, it dies Apoptosis: Programmed cell death Cells going through apoptosis actually shrink and shrivel in a controlled process. It is normal

Examples of Apoptosis:

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong.

What happens if these check points are not functioning?

Abnormal Cell Cycle: Cancer Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Abnormal Cell Cycle: Cancer Cancer is the uncontrolled growth and division of cells. Cancer cells can kill an organism by crowding out normal cells, resulting in the loss of tissue function.

Causes of Cancer What causes cancer? Cell mutations Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Causes of Cancer What causes cancer? Cell mutations Various environmental factors and genetic factors can affect the occurrence of cancer cells.

Specialized Cells

How do cells become specialized?

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Stem Cells Unspecialized cells that can develop into specialized cells when under the right conditions

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Embryonic Stem Cells After fertilization, the resulting mass of cells divides repeatedly until there are about 100–150 cells. These cells have not become specialized. Scientists are finding ways to make them turn into specific, needed cells

Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation Adult Stem Cells Found in various tissues in the body and might be used to maintain and repair the same kind of tissue Less controversial because the adult stem cells can be obtained with the consent of their donor