3. What is Mitosis? Mitosis: Cell division involving somatic (non- sex) cells Involves only diploid cells End Result: Two genetically identical “daughter cells”

4. The Cell Cycle Defined: Repeating set of events in the life of a cell 1) Interphase –G1, S, G2 2) Prophase 3) Metaphase 4) Anaphase 5) Telophase mitosis

5. Interphase Divided into 3 Stages: G1 Stage –Normal function performed –Cell growth –Organelles created S Stage –Chromatin (DNA strands) duplicated G2 Stage –Cell growth –Normal function performed

6. Prophase 1 st Mitosis Stage Chromatin (DNA strands) coils into chromosomes Nucleus dissolves Spindle fibers form

7. Metaphase 2 nd stage of mitosis Spindle fibers attach to centromere of chromosome Spindle fibers pull chromosomes to cell equator

8. Anaphase 3 rd stage of mitosis Spindle fibers pull ½ the chromatids to each end of the cell –Humans: 46 chromatids each way

9. Telophase 4 th stage of mitosis Spindle fibers dissolve Chromatids unwind into chromatin Nucleus reforms Cytokinesis: division of the cytoplasm –NOT APPART OF TELEPHASE

10. Nice animation of mitosis

12. Name that Stage! Hint: Chromosomes are aligned in middle of cell

13. Name that Stage! Hint: Cell plate is splitting the cell

14. Name that Stage! Hint: Two normal looking nuclei of two cells

15. Name that Stage! Hint: Chromosomes are forming and the nucleus is gone

16. Name that Stage! Hint: Chromatids are being pulled apart

18. Name this stage of the cell cycle.

31. Mitosis A Quick Overview

33. Aging Normal process –Observable changes in the body’s structure & function –Decreases the body’s ability to maintain homeostasis Cessation of mitosis –Cells only divide a certain number of times & then stop –May be programmed genetically Telomeres: Pieces of DNA found at the tips of each chromosome. –Protect the chromosome from losing base pairs –Guard against chromosomes sticking to each other –Each time a cell divides its chromosomes’ telomeres shorten. After many divisions important parts of the DNA sequence may erode causing aging and or the death of cells. Glucose –Gets added to proteins inside & outside our cells creating links between cells Contributes to loss of elasticity and stiffening of tissues. Free radicals –Cause damage to our carbon based molecules –Enzymes produced by organelles in our cells are suppose to break them down –Eating foods high in antioxidants (Vit C, E, betacarotene, selenium, etc) help combat the oxidation

34. REview 1)In order, name the 5 stages of the cell cycle. 2)Pick a stage of the cell cycle. Name 2 things that happen in this stage. 3)Review the picture slides. Identify the stages based on the picture. 4)The division of the cytoplasm is called _____. 5)Which cells divide by mitosis? 6)During which interphase stage is DNA created? 7)During which stage do spindle fibers form? 8)During which stage are chromosomes aligned in the middle? 9)During which stage are chromatids separated? 10)During which stage does the nucleus dissolve? 11)What are telomeres and what do they do?