1. WARM UP #3 1/26 1.What is happening in the picture? 2.How many chromosomes is this cell starting with? 3.How many chromosomes in each cell is it ending with? 4.How many cells are made in the end? 5.Name any PHASES you remember

2. TODAY 1/26 1.Video comparing mitosis to meiosis – sheet 2.Finish notes #2 from yesterday 3.Practice sheet SAME LEARNING TARGET I can describe and identify the steps of cell division and compare mitosis and meiosis.

3. MITOSIS – review of what we saw yesterday http://www.johnkyrk.com/mitosis.html MEIOSIS comparing http://www.youtube.com/watch?v=Ba9LXKH 2ztU&feature=related

4. CHAPTER 11 NOTES #2 MITOSIS and MEIOSIS

5. MITOSIS In SOMATIC CELLS only - body cells (skin, muscle, bone, etc) 1 cell divides to make ______ cells End with __________ # of chromos = DIPLOID EX: start with 46, end with _____ * STEPS: _________________________ MEIOSIS In GAMETES only – sex cells (eggs and sperm) 1 cell divides to make _____ cells End with __________ # of chromos = HAPLOID EX: start with 46, end with _____ * STEPS: __________________________ 2 WAYS THAT CELLS DIVIDE

6. Why need meiosis?

8. MAIN PHASES of MITOSIS and MEIOSIS: INTERPHASE - when the cell is not dividing (resting) Chromosomes seen as single strands

9. 1. PROPHASE Chromosomes doubled – look like X’s

10. 2. METAPHASE Chromosomes line up in middle

11. METAPHASE – MEIOSIS Instead of lining up single file, they line up in pairs of 2 (homologous pairs) CROSSING OVER CAN HAPPEN Mixes up genes for more variation

12. 3. ANAPHASE Chromosomes are pulled apart

13. 4) TELOPHASE Cell splits into two

14. MEIOSIS – goes through phases again END 4 cells with ½ the # of chromos.

15. REVIEW: WHAT PHASE?

17. MITOSIS AS SEEN IN OUR CELLS

18. PRACTICE ASSIGNMENT Use your notes and diagram to answer the questions, if not complete today, then it becomes homework.

20. MITOSIS RATES DO all cells go through mitosis at same rate? NO EX: stomach cells fast, liver cells slow AGING – mitosis slows down - cells don’t repair or replace as fast CANCER – mitosis speeds up of abnormal cells

21. CELL CYCLE The time the cells spend in each phase