1 / 21

Meiosis

Meiosis. Division of Sex Cells. Meiosis. A process of cell division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell; formation of gametes Diploid – 2 sets of chromosomes (2 copies of each)

awen
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 Division of Sex Cells

  2. Meiosis • A process of cell division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell; formation of gametes • Diploid – 2 sets of chromosomes (2 copies of each) • Haploid – 1 set of chromosomes (1 copy of each) • Homologous – chromosomes that each have a corresponding chromosome from the opposite sex parent (1 from father, 1 from mother)

  3. Meiosis Stages • Meiosis usually involves 2 distinct stages • Meiosis I • Meiosis II

  4. Prophase I (Meiosis I) • Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. • There are 4 chromatids in a tetrad. • Crossing-over may occur here • Crossing-over is when chromosomes overlap and exchange portions of their chromatids.

  5. Prophase I

  6. Metaphase I • Spindle fibers attach to the chromosomes • Chromosomes line up in the middle of the cell

  7. Metaphase I

  8. Anaphase I • The fibers pull the homologous chromosomes toward opposite ends of the cell.

  9. Anaphase I

  10. Telophase I & Cytokinesis • Nuclear membranes form. • The cell separates into 2 cells.

  11. Telophase I

  12. Prophase II (Meiosis II) • Meiosis I results in two haploid (N) cells. • Each cell has half the number of chromosomes as the original cell.

  13. Prophase II

  14. Metaphase II • The chromosomes line up similar to metaphase in mitosis.

  15. Metaphase II

  16. Anaphase II • Sister chromatids separate and move to opposite ends of the cell.

  17. Anaphase II

  18. Telophase II • Meiosis II results in 4 haploid cells.

  19. Telophase II

  20. Gamete Formation • In males, meiosis results in 4 sperm cells • In females, meiosis results in 1 egg cell and three polar bodies, which are not used in reproduction.

  21. Mitosis vs Meiosis

More Related