Section 5-3 & 5-5 “Cancer & Stem Cells ”

Section 5-3 & 5-5“Cancer & Stem Cells” Write everything that isunderlined

5.3 KEY CONCEPTCell cycle regulation is necessary for healthy growth

I. Cell Division1. 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

webbed fingers 2. Apoptosis is programmed cell death • a normal feature of healthy organisms • caused by a cell’s production of self-destructive enzymes • occurs indevelopmentof infants

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

normal cell cancer cell bloodstream

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

5. Carcinogens are substances known to cause cancer 6. Standard cancer treatments typically kill both cancerous and healthy cells

5.5 KEY CONCEPT Cells work together to carry out complex functions

Inner: intestines Outer: skin cells Middle: bone cells I. Specialized Cells1. Specialized cells perform specific functions. • Cells develop into their mature forms through the process of cell differentiation 2. Cells are different because different combinations of genes are expressed • A cell’s location in an embryo helps determine how it will differentiate

II. Stem Cells1. 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

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. • Adult stem cells can be hard to isolate and grow. • The use of adult stem cells may prevent transplant rejection. • The use of embryonicstem cells raisesethical issues • Embryonic stem cellscan be grown indefinitelyin culture. • Stem cells come from adults and embryos

Section 5-3 & 5-5 “Cancer & Stem Cells ”