1. The Cell Cycle (Somatic Cells)

2. Vocabulary Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

3. The Cell Cycle for Somatic Cells All cells come from cells. To grow and divide (how new cells are made) cells undergo an orderly sequence of events. First, a cell must copy its DNA (in its chromosomes). The DNA copies must separate into two sides of the cell. The cell then splits into 2 identical cells. So…one skin cell divides into two skin cells, one bone cell divides into two bone cells, one muscle cell divides into two muscle cells, etc.

4. Mitosis: The part of the cell cycle in which the nucleus divides to form two identical nuclei.

5. Interphase (occurs just before Mitosis begins) The cell grows in size. DNA (in the chromatin) and organelles (such as centrioles) are replicated (copied). The cell prepares for division. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm Chromatin - (loose threads of DNA in the nucleus of a cell)

6. Interphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

7. 1 st step in Mitosis: Prophase (preparation phase) http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm The chromatin (duplicated DNA) coils and condenses into chromosomes. The nuclear membrane disappears. The spindle fibers begin to form.

8. Mitosis Prophase Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Animal cell Plant cell

9. 2 nd step in Mitosis: metaphase (organizational phase) The chromosomes line up in the middle of the cell. The spindle fibers attach to the centromere of each replicated chromosome. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

10. Mitosis Metaphase Animal cellPlant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

11. 3 rd step in Mitosis: Anaphase (separation phase) The chromosomes split in the middle and the sister chromatids are pulled by the spindle fibers to opposite sides of the cell. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

12. Mitosis Anaphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

13. 4 th step in Mitosis: Telophase The chromosomes, along with the cytoplasm and its organelles and membranes are divided into 2 portions. This diagram shows the end of telophase. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

14. Mitosis Telophase Animal cellPlant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

15. After Mitosis: Cytokinesis The actual splitting of the daughter cells into two separate cells is called cytokinesis and occurs differently in both plant and animal Cells. Beginning of cytokinesis in a plant: Beginning of cytokinesis in an animal: http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

16. Interphase Prophase Metaphase Anaphase Telophase Cytokinesis IPMATC

17. Meiosis Vocabulary Diploid Cells – have pairs of similar chromosomes. Somatic Cells – are diploid cells. Haploid Cells – do NOT have pairs of chromosomes (have HALF the number of chromosomes that somatic cells have). Gametes – are haploid sex cells.

18. Meiosis is the process of cell division that results in gametes(sex cells, sperm and egg). Gametes (haploid number of chromosomes) are needed for sexual reproduction. In sexual reproduction, the new organism gets half of its chromosomes from one parent (mother via the egg)and half from another parent (father via the sperm).

20. Before Meiosis: Interphase The chromosomes have replicated, and the chromatin begins to condense. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

21. Meiosis Prophase I The chromosomes are completely condensed. In meiosis (unlike mitosis), the homologous chromosome pairs join together. While the homologous chromosomes are joined, they exchange DNA (called crossing over). http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

22. Meiosis Metaphase I The nuclear membrane dissolves and the homologous chromosomes attach to the spindle fibers. They are preparing to go to opposite poles. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

23. Meiosis Anaphase I The chromosomes move to opposite ends of the cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

24. Meiosis Telophase I & Cytokinesis The cell begins to divide into two daughter cells. It is important to understand that each daughter cell can get any combination of maternal or paternal chromosomes. So…the daughter cells are NOT identical copies of each other (unlike mitosis). http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

25. Meiosis Prophase II The cell has divided into two daughter cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

26. Meiosis Metaphase II As in Meiosis I, the chromosomes line up on the spindle fibers. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

27. Meiosis Anaphase II The two cells each begin to divide. The chromosomes separate and the sister chromatids move to opposite ends of each cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

28. Telophase II & Cytokinesis With the formation of four cells, meiosis is over. Each of these prospective germ cells carries half the number of chromosomes of somatic cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

29. For Example: SpeciesSomatic Cells (diploid number results from MITOSIS) Gametes (haploid number results from MEIOSIS) Human4623 Fruit Fly84 Adders-tongue fern1440720

30. This may you remember these terms: MITosis takes the cell and Makes It Two (diploid) Meiosis has to do with sexual reproduction Meiosis results in an egg or sperm. Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York

31. MitosisMeiosis