1. Mitosis: Cell Division

2. Terminology DNA – made of nucleic acids, housed in the nucleus, contains genes Chromatin – long strands of DNA that are wrapped around proteins (histones) Nucleosome – the DNA/ histone complex

3. Why does mitosis happen? Surface area to volume ratio –As a cell grows, the volume grows faster than the surface area –Not enough space in the cell membrane to send wastes out or to bring food in Signal is sent to the cell –An organism needs to grow –To repair damage

4. Structure of a Chromosome Chromosome – a structure that is made of DNA and the proteins associated with it Chromatid – one of the 2 exact copies of the DNA – often referred to as “sister chromatids” – the 2 of them together make a chromosome Centromere – the point where the 2 chromatids are connected together to make a chromosome

5. Homologous Chromosomes two chromosomes that code for the same traits. One is from mom the other is from dad

6. Cell Cycle Interphase –Majority of a cell’s life –Cell grows –Chromosomes duplicate Mitosis –Creates 2 daughter cells that are identical to the parent cell –Cell division

7. Interphase G1 –Growth One –The cell spends most of its life S –Chromosomes are duplicated G2 –Organelles and other parts needed for cell division are duplicated

8. Mitosis Prophase – the chromosomes become visible – the nuclear envelope disappears – pro = first Metaphase – the chromosomes line up in the middle of the cell Anaphase – the sister chromatids move away from each other Telophase – begins as chromatids reach opposite ends of the cell

9. Cytokinesis The cytoplasm and organelles are divided between the two sides Plants: –A cell plate begins forming Animals: –A cleavage furrow forms as the cell pinches inward

10. Levels of Organization

11. When Good Cells Go Bad! Who will develop it? –½ of men and 1/3 of women in the U.S. will develop cancer in their lifetime What is it? –Uncontrolled cell division What causes the cell to keep dividing? –Failure to produce internal regulators or respond to external regulators Facts about cancer

12. Causes of Cancer a. Tobacco use – lung, mouth, esophageal, cervical cancer b. Asbestos – lung cancer c. Radiation exposure d. Viral infection - HPV e. Charred meat – colon cancer f. Genetic g. Chemical exposure h. UV exposure (sun or tanning bed) – skin cancer i. Drinking more than one drink a day for women or 2 a day for men

13. Kinds of Cancer Metastatic –More dangerous –Cancer travels in the body Nonmetastatic –Usually less dangerous –Cancer does not travel Not all cancers form tumors and not all tumors are cancerous!

14. How does cancer spread? Pancreatic Cancer