1 / 17

Meiosis

Meiosis. Image found on www.accessexcellence.org. Why is there Meiosis?. TO MAKE SEX CELLS WHICH ARE HAPLOID. Synapsis: the process when homologous chromosomes come together Tetrad: the structure formed when the chromosomes come together . “x” structure

fuller-knight
Download Presentation

Meiosis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Meiosis

  2. Image found on • www.accessexcellence.org

  3. Why is there Meiosis? • TO MAKE SEX CELLS WHICH ARE HAPLOID

  4. Synapsis: the process when homologous chromosomes come together Tetrad: the structure formed when the chromosomes come together . “x” structure Chiasmata-the site of crossing over of non sister chromatids MEIOSIS 1 • As in mitosis, meiosis 1 is preceded by the synthesis of DNA and replication of chromosomes: So we could call this Interphase 1

  5. Prophase I • The chromatin begins to coil into short rods and homologous chromosomes are formed • Spindle fibers appear and nucleus brakes down • The nuclear membrane is gone at end. Image found: taggart.glg.msu.edu/bs110/meiosis.htm

  6. Metaphase I • Tetrads become attached to spindle fibers • Crossing Over occurs • Image may be found on www.mnsu.edu/.../sourceofgenetic variation.html

  7. Anaphase I • Homologous chromosomes separate • Reducing process • 2n to n • Next two slides Images found on library.thinkquest.org/…/media/prophase-1.gif

  8. Telophase I • The chromosomes reach the end of the cell. Cytokinesis takes place. Two daughter cells are produced • Nucleus,nuclear membrane, cytoskeleton, nucleolus reappear • DNA uncoils

  9. Meiosis II • The following 6 slides have pictures found on www.pbs.org/wgbh/nova/miracle/divi_text_09.html

  10. Interphase II • NO DNA replication

  11. Prophase II • DNA coils • Mitotic spindle forms • Nucleolus disappears • Nuclear membrane disappears • Nucleus disappears

  12. Metaphase II • Sister chromatids line up at the equator

  13. Anaphase II • Centromere splits • Chromosomes are pulled to opposite poles

  14. Telophase II • Mitotic spindles break down, nucleolus, nuclear membrane, nucleus, reforms • DNA uncoils • Cytokinesis

  15. What is the result of Meiosis? • 4 daughter cells • haploid

  16. Spermatogenesis • The production of sperm cells • Image found on users.rcn.com/…/S/Sexual_Reproduction.html

  17. OOGENESIS • Production of mature egg cells • During meiosis the cytoplasm of original cell is divided unequally between new cells • One cell gets most of cytoplasm. This becomes the egg and the other 3 cells are called polar bodies, which eventually degenerate • Image found on www.columbia.edu/.../hand-1.htmlhand-1a.html

More Related