Meiotic Cell Division
<ul><li>Sexual reproduction is the most common way for eukaryotic organisms to produce offspring </li></ul><ul><li>Parents...
<ul><li>Most eukaryotic species are  heterogamous </li></ul><ul><ul><li>These produce gametes that are morphologically dif...
How Does One Make a Haploid Gamete? <ul><li>Answer – meiosis </li></ul><ul><li>Haploid cells are produced from diploid cel...
Mitosis   vs   Meiosis <ul><li>Produces two diploid daughter cells </li></ul><ul><li>Produces daughter cells that  ARE  ge...
<ul><li>Meiosis begins after a cell has progressed through G 1 , S, & G 2 </li></ul><ul><li>Meiosis involves two successiv...
Periods of Prophase I A physical exchange of chromosome pieces A   tetrad
Stages of Meiosis I Spindle apparatus complete; pairs of chromatids attached to kinetochore microtubules
<ul><li>Tetrads are organized along the metaphase plate </li></ul><ul><li>Homologous  p airs of sister chromatids  aligned...
Stages of Meiosis I 3-50 Homologous chromosomes separate from each other The centromere remains between sister chromatids
Meiosis  <ul><li>Telophase I & cytokinesis of meiosis I is followed meiosis II </li></ul><ul><li>Meiosis I has reduced the...
Stages of Meiosis II 1 of each type of chromosome (n) in each daughter cell (gamete)
Separation of Alleles During Meiosis Prophase I Metaphase I Anaphase I Telophase I Meiosis II Haploid cells Heterozygous (...
Separation of Alleles During Meiosis Meiosis I Meiosis II or 2  Ry : : Heterozygous diploid cell ( YyRr ) to undergo meios...
Credits <ul><li>Images </li></ul><ul><li>Campbell, N.A., & Reece, J.B. (2005).  Biology  (7 th  ed.). San Francisco, CA:  ...
Upcoming SlideShare
Loading in...5
×

Meiosis Lecture

1,032

Published on

Meiosis lecture for CHS IB Biology HL Year 1

Published in: Education, Technology
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,032
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
12
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Meiosis Lecture

  1. 1. Meiotic Cell Division
  2. 2. <ul><li>Sexual reproduction is the most common way for eukaryotic organisms to produce offspring </li></ul><ul><li>Parents make gametes with half the amount of genetic material ( haploid ) </li></ul><ul><li>These gametes fuse with each other during fertilization to generate a new organism </li></ul>Sexual Reproduction
  3. 3. <ul><li>Most eukaryotic species are heterogamous </li></ul><ul><ul><li>These produce gametes that are morphologically different </li></ul></ul><ul><ul><ul><li>Sperm cells </li></ul></ul></ul><ul><ul><ul><ul><li>Relatively small and mobile </li></ul></ul></ul></ul><ul><ul><ul><li>Oocytes or ova </li></ul></ul></ul><ul><ul><ul><ul><li>Usually large and nonmobile </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Store large amounts of nutrients </li></ul></ul></ul></ul><ul><ul><ul><li>Microspores (Pollen) </li></ul></ul></ul><ul><ul><ul><li>Macrospores (Ovules) </li></ul></ul></ul>Gametes
  4. 4. How Does One Make a Haploid Gamete? <ul><li>Answer – meiosis </li></ul><ul><li>Haploid cells are produced from diploid cells during gametogenesis </li></ul><ul><li>The chromosomes must be distributed to reduce the chromosome number to half its original value </li></ul><ul><li>but simultaneously sorted to assure that each chromosome (& its genes) is represented in each gamete </li></ul>
  5. 5. Mitosis vs Meiosis <ul><li>Produces two diploid daughter cells </li></ul><ul><li>Produces daughter cells that ARE genetically identical </li></ul><ul><li>Produce four haploid daughter cells </li></ul><ul><li>Produces daughter cells that are NOT genetically identical </li></ul>
  6. 6. <ul><li>Meiosis begins after a cell has progressed through G 1 , S, & G 2 </li></ul><ul><li>Meiosis involves two successive divisions </li></ul><ul><ul><li>Meiosis I and II </li></ul></ul><ul><ul><li>Each of these is subdivided into </li></ul></ul><ul><ul><ul><li>Prophase </li></ul></ul></ul><ul><ul><ul><li>Metaphase </li></ul></ul></ul><ul><ul><ul><li>Anaphase </li></ul></ul></ul><ul><ul><ul><li>Telophase </li></ul></ul></ul>Meiosis
  7. 7. Periods of Prophase I A physical exchange of chromosome pieces A tetrad
  8. 8. Stages of Meiosis I Spindle apparatus complete; pairs of chromatids attached to kinetochore microtubules
  9. 9. <ul><li>Tetrads are organized along the metaphase plate </li></ul><ul><li>Homologous p airs of sister chromatids aligned side by side </li></ul><ul><ul><li>A pair of sister chromatids is linked to one of the poles </li></ul></ul><ul><ul><li>And the homologous pair is linked to the opposite pole </li></ul></ul><ul><ul><li>The arrangement is random with regards to the ( blue and red ) homologues </li></ul></ul>Figure 3.13
  10. 10. Stages of Meiosis I 3-50 Homologous chromosomes separate from each other The centromere remains between sister chromatids
  11. 11. Meiosis <ul><li>Telophase I & cytokinesis of meiosis I is followed meiosis II </li></ul><ul><li>Meiosis I has reduced the number of chromosomes in the daughter cells to the ½ the diploid number </li></ul><ul><li>However, each homolog is still composed of 2 recombinant sister chromatids </li></ul><ul><ul><li>The genetic content is still 2n </li></ul></ul><ul><li>Meiosis II reduces the genetic content to n </li></ul>
  12. 12. Stages of Meiosis II 1 of each type of chromosome (n) in each daughter cell (gamete)
  13. 13. Separation of Alleles During Meiosis Prophase I Metaphase I Anaphase I Telophase I Meiosis II Haploid cells Heterozygous ( Yy ) cell from a plant with yellow seeds y y y y y y y Y Y Y Y Y Y Y
  14. 14. Separation of Alleles During Meiosis Meiosis I Meiosis II or 2 Ry : : Heterozygous diploid cell ( YyRr ) to undergo meiosis y y y y y y y y y Y Y Y Y Y Y Y Y Y R R R r r y r r R R Y R R R R y R r r r r Y r Y y R r R r r 2 rY 2 ry 2 RY
  15. 15. Credits <ul><li>Images </li></ul><ul><li>Campbell, N.A., & Reece, J.B. (2005). Biology (7 th ed.). San Francisco, CA: Pearson </li></ul>
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×