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DO NOW!

DO NOW!. What does PMAT stand for? What happens during telophase ? What happens during metaphase?. Agenda. Science fair projects are late . Parent Letters…I only have about 20 Many of you did not complete the Protists /Organelles Open Book Test—If you did not, please see me.

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DO NOW!

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  1. DO NOW! • What does PMAT stand for? • What happens during telophase? • What happens during metaphase?

  2. Agenda • Science fair projects are late. • Parent Letters…I only have about 20 • Many of you did not complete the Protists/Organelles Open Book Test—If you did not, please see me. • Notebook Check tomorrow • Mitosis Review • Meiosis • What is it? • Why do we have it? • Why is it important?

  3. Mitosis Review…for some Candy… • What are the steps of mitosis? • What is the purpose of mitosis? • Is it asexual or sexual? Why?

  4. Vocabulary • Gamete: Sex Cell (sperm or egg) • Diploid: Have pairs of chromosomes • Haploid: Have half the number of chromosomes • Zygote: Combination of Sex Cells after fertilization • Homogolous: Matching pairs

  5. Diploid vs. Haploid http://www.youtube.com/watch?v=MU83VWAvUf4

  6. MEIOSIS is… • Meiosis is a form of cell division that produces SEX CELLS (gametes), such as sperm and egg. • Gametes are haploid; they have only half the number of chromosomes as a normal body cell. • Fertilization restores the chromosomes in body cells to the diploid number.

  7. Purpose of Meiosis • Produce haploid eggs and sperm (23 chromosomes in humans) • Meiosis consists of two cell divisions. • Meiosis I separates pairs of homologous chromosomes (46 chromosomes in each cell) • Meiosis II separates sister chromatids (23 chromosomes in each egg or sperm)

  8. Simplified… • MEIOSIS creates the variety we see among individuals (animals, plants, etc.) because it leads to the mixing of genetic information

  9. Phases of Mitosis • Two phases! • Remember PMAT? • Prophase, Metaphase, Anaphase, Telophase? • In Meiosis there is PMAT TWICE

  10. So is Meiosis Sexual or Asexual? For candy, tell me which one and why….

  11. Some things to look at: • http://www.cellsalive.com/meiosis.htm • http://www.youtube.com/watch?v=D1_-mQS_FZ0 • http://www.youtube.com/watch?v=iCL6d0OwKt8

  12. Mitosis vs. Meiosis • During prophase I: The chromosomes become visible and the centrioles begin forming spindle fibers • At this stage each chromosome is split into two sister chromatids. • The paired chromosomes now have four chromatids (2 sets of 'sisters') pressed together. • Crossing over takes place between two of the non-sister chromatids; the other two remain uncrossed. The crossover results in the exchange chromosomes.

  13. SO TO REMEMBER… • Mitosis— • Growth, Repair, and reproduction of simple cells • One cell to two identical offspring cell • Asexual • PMAT • Meosis— • Reproduction process to create sperm and eggs • One cell to four different offspring cells with half the number of chromosomes • Sexual Reproduction process • PMATPMAT

  14. How do cells divide in meiosis?

  15. Exit Ticket Meiosis Mitosis

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