2. Sexual Reproduction and Meiosis

3. Sexual Reproduction How new organisms are produced 2 new cells come together Formed from cells in reproductive organs

4. Sex Cells in Humans Male reproductive organs contain sex cells called sperm Female reproductive organs contain sex cells called eggs

5. Meiosis I Chromosomes become duplicated There are 4 Phases: Prophase I, Metaphase I, Anaphase I and Telophase I

6. Prophase I Duplicated chromosomes are visible under a microscope as a chromatid Duplicated chromosome comes near its duplicated mate

7. Metaphase I Duplicated chromosome pairs line up in center of cell The centromere of each pair becomes attached to one spindle fiber The chromatids do not separate

8. Metaphase I

9. Anaphase I 2 pairs of chromatids move away to opposite ends of the cell Duplicated chromosome still have 2 chromatids

10. Telophase I The cytoplasm divides 2 new cells form New cell has 1 duplicated chromosome from each similar pair

11. Telophase I

12. Meiosis II Begins after 2 new cells form in Meiosis I Chromatids of each chromosome will be separated during this division Occurs in 4 phases: Prophase II, Metaphase II, Anaphase II, Telophase II

13. Prophase II The duplicated chromosomes and spindle fibers reappear in each new cell

14. Metaphase II Duplicated chromosomes move to the center of cell Each centromere attaches to 2 new spindle fibers

15. Anaphase II Centromere divides Chromatids separate and move to opposite ends of the cell Each chromatid is now an individual chromosome

16. Telophase II Spindle fibers disappear Nuclear membrane forms around the chromosomes at each end of the cell Cytoplasm divides

17. How Fast Does Meiosis Happen? Just how fast does meiosis happen? Is it faster than a car going 100 mph or is it slower than a turtle crawling? Lets find out!

18. Meiosis! Meiosis! Meiosis! Now that you are an expert on Meiosis, let’s see how well you can identify each step Name each of the following steps from Meiosis I or II.

19. Name this step. Metaphase 2! That’s right!

20. Which step is this? Telophase I! That’s right!

21. Is this step from Meiosis I or II? Meiosis I! That’s right!

22. Meiosis! Cells have been divided, chromosomes duplicated, we have reached the end of meiosis…. See you next class!

23. Webliography Pictures taken from Microsoft Clip Art http://www.sumanasinc.com/webcontent/animations /content/meiosis.htmlhttp://www.sumanasinc.com/webcontent/animations /content/meiosis.html http://www.uic.edu/classes/bios/bios100/lecturesf04 am/prophase1m.jpghttp://www.uic.edu/classes/bios/bios100/lecturesf04 am/prophase1m.jpg www.biologycorner.com/bio1/qz_meiosis.html Information taken from Glencoe LifeScience Book A http://videos.howstuffworks.com/hsw/5988-mitosis- and-meiosis-metaphase-one-video.htmhttp://videos.howstuffworks.com/hsw/5988-mitosis- and-meiosis-metaphase-one-video.htm http://www.usd.edu/~bgoodman/cell.JPG