1. Section 5-3 & 5-5 Cancer & Stem Cells Section 5-3 & 5-5 Cancer & Stem Cells Write everything that is underlined

2. 5.3 Cancer / 5.5 Stem Cells 5.3 KEY CONCEPT Cell cycle regulation is necessary for healthy growth

3. 5.3 Cancer / 5.5 Stem Cells I. Cell Division 1. Internal and external factors regulate (control) cell division a. External factors include physical and chemical signals b. Growth factors are proteins that stimulate cell division –Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells

4. 5.3 Cancer / 5.5 Stem Cells –a normal feature of healthy organisms –caused by a cells production of self- destructive enzymes –occurs in development of infants webbed fingers 2. Apoptosis is programmed cell death

5. 5.3 Cancer / 5.5 Stem Cells II. Cancer Cells 1. Cell division is uncontrolled in cancer 2. Cancer cells form disorganized clumps called tumors –Benign (good) tumors remain clustered and can be removed –Malignant (bad) tumors metastasize, or break away, and can form more tumors

6. 5.3 Cancer / 5.5 Stem Cells cancer cell bloodstream normalcell

7. 5.3 Cancer / 5.5 Stem Cells 3. Cancer cells do not carry out their necessary functions 4. Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation

8. 5.3 Cancer / 5.5 Stem Cells 5. Carcinogens are substances known to cause cancer 6. Standard cancer treatments typically kill both cancerous and healthy cells

9. 5.3 Cancer / 5.5 Stem Cells 5.5 KEY CONCEPT Cells work together to carry out complex functions

10. 5.3 Cancer / 5.5 Stem Cells I. Specialized Cells 1. Specialized cells perform specific functions. Cells develop into their mature forms through the process of cell differentiationCells develop into their mature forms through the process of cell differentiation 2. Cells are different because different combinations of genes are expressed A cells location in an embryo helps determine how it will differentiateA cells location in an embryo helps determine how it will differentiate Outer: skin cells Middle: bone cells Inner: intestines

11. 5.3 Cancer / 5.5 Stem Cells II. Stem Cells 1. Stem cells are unique body cells. 2. Stem cells have the ability to: –divide and renew themselves –remain undifferentiated in form –develop into a variety of specialized cell types

12. 5.3 Cancer / 5.5 Stem Cells First, an egg is fertilized by a sperm cell in a petri dish. The egg divides, forming an inner cell mass. These cells are then removed and grown with nutrients. Scientists try to control how the cells specialize by adding or removing certain molecules. Stem cells come from adults and embryosStem cells come from adults and embryos –Adult stem cells can be hard to isolate and grow. –The use of adult stem cells may prevent transplant rejection. –The use of embryonic stem cells raises ethical issues –Embryonic stem cells can be grown indefinitely in culture.