1 / 20

MEIOSIS

Learn about the purposes of meiosis, which include producing gametes, reducing the number of chromosomes in gamete cells, and increasing genetic diversity. Discover how meiosis works in cells to create haploid cells from diploid cells.

sharley
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. WHAT ARE THE PURPOSES OF MEIOSIS? • TO MAKE GAMETES (EGGS AND SPERM) • 2. TO REDUCE THE NUMBER OF CHROMOSOMES IN GAMETE CELLS BY ONE-HALF • 3. TO INCREASE THE GENETIC DIVERSITY IN GAMETES

  3. Chromosomes are found in pairs: Human Karyotype

  4. Each pair is a homologouspair:

  5. Homologous pairs of chromosomes have genes for the same traits at the same location on the chromosome

  6. One chromosome of a homologous pair comes from the organism’s mother, and the other comes from the organism’s father

  7. Cells where all the chromosomes are in pairs are called DIPLOID, which means they have TWO of each chromosome • Abbreviated ‘2N’, where N = the number of pairs of chromosomes • Humans have 23 pairs of chromosomes, so in humans 2N = 46 • In humans, ALL cells except for eggs and sperm are 2N • Egg and sperm only have ONE chromosome from each pair (half of the chromosomes, so they are called HAPLOID cells, abbreviated ‘N’

  8. How do cells make haploid cells from diploid cells? • Meiosis! (pronounced my-osis) • In meiosis, the number of chromosomes is reduced by one-half AND genetic diversity is increased

  9. Meiosis has two sets of divisions called Meiosis I and Meiosis II

  10. MEIOSIS I

  11. TETRAD FORMATION:

  12. INTERPHASE II: NO DNA REPLICATION!

  13. MEIOSIS II

  14. So, from one diploid (2N) cell, meiosis makes: • FOUR haploid (N) cells • And ALL of those haploid cells are genetically different (have different DNA)

More Related