1. Mitosis,9-2 Division of regular body,(somatic) cells

2. Mitosis Division of somatic cells (body) Somatic Cell Daughter Cells

3. Chromosomes Strands of DNA Each human has 23 pair (diploid or 2n) –One from your mother –One from your father –Chromatin- uncoiled or unpacked chromosomes –Chromosome- coiled up or tightly packed chromosomes

4. Chromosome One from Mom One from Dad Sister chromatids DNA molecule with attached proteins Look at figure 8.2

5. Summary of DNA Nucleotides- the genetic code (sugar, base, phosphate) Nucleic acid- chain of nucleotides DNA- double stranded double helix with hydrogen bonds between strands Nucleosome- DNA wrapped around histones Sister chromatids- formed prior to mitosis Two copies of each chromosome- one from each parent (diploid) 23 Chromosomes per human in somatic cells

6. Mitosis First you duplicate DNA Why? –You have 2 pairs of 23 chromosomes –If cell splits, you will only have 1 pair –Duplicate DNA, cell splits, still have 2 pair Sex chromosomes- X and Y: XX is female in humans, XY is male

7. Interphase, THESE CELLS ARE NOT “RESTING” Prior & After Mitosis G1 period –90% of cell life spent here –Cell goes about it’s business S period –DNA is duplicated G2 period –Cell prepares to divide Cannot see DNA- uncoiled as chromatin

8. 1. Prophase DNA becomes visible as chromosomes Nuclear membrane dissolves Centrioles migrate to opposite poles Spindle fibers form Easy to remember- Prophase- proceeding into mitosis

9. 2. Metaphase Spindle fibers attach to centromeres Chromosomes line up at midline of the cell Easy to remember- metaphase, DNA at middle Spindle Equator Pole

10. 3. Anaphase Spindle fibers pull apart centromeres One chromatid goes to each centriole (they look like V’s) Easy to remember- anaphase, apart they go

11. 4. Telophase Chromatids reach centrioles Mitosis ends when new nuclear membranes form Some evidence of cell dividing Easy to remember- telophase, terminal phase

12. Last part- Cytoplasmic division Technically not in mitosis –Animal cell- pinching of cell membrane- cleavage –Plant cell- formation of new cell wall- cell plate –Also, plant cells don’t have centrioles, they use a different mechanism. –DNA becomes non-visible, back to chromatin Daughter cells enter G1 period of interphase

13. Cancer Uncontrollable mitosis (no G1) –Cells cease to do what they are supposed to be doing in favor of dividing. Pancreatic cancer- no longer in interphase Cease production of insulin Incomplete digestion of food Diabetes, abdominal pain, weight loss Cancer does not “poison” your body…