9 5 Meiosis in Sexual Reproduction Haploid cells
- Slides: 14
9. 5 Meiosis in Sexual Reproduction
Haploid cells have only one set of chromosomes, abbreviated as “n” Diploid cells are those with two (di) sets = “ 2 n” Gametes = Haploid Sex Cells (sperm/egg)
Homologous chromosomes: A pair of chromosomes in which one member of the pair is obtained from the organism's maternal parent and the other from the paternal parent; found in diploid cells. Already duplicated in preparation for division
Humans _____Chromosomes, ______Pairs One from Mom One from Dad 2 Gametes (n) join during fertilization forming a 2 n cell called a Zygote.
Mitosis starts with 1 2 n cell ends with 2 2 n cells genetically identical Meiosis starts with 1 2 n cell ends with 4 n cells genetically mixed
Two divisions occur, Meiosis I (Reduction) and Meiosis II (Division) Prophase I Unique Event!!! Homologues group forming tetrads - Crossing over occurs - chromatids break and may be reattached to a different homologous chromosome
Metaphase I - tetrads line-up along the equator of the spindle. Spindle fibers attach to the centromere region of each homologous chromosome pair Anaphase I - tetrads separate, and are drawn to opposite poles by the spindle fibers. The centromeres in Anaphase I remain intact.
Telophase 1 & Cytokinesis occurs NO INTERPHASE AKA NO DNA REPLCIATION PMAT STARTS ALL OVER AGAIN Prophase II Metaphase II Anaphase II Telophase II Occur similar to mitosis.
Possible gamete combinations = 2 n where n is the number of chromosomes So humans its 223 Or 8, 400, 000 possible gamete combinations!
- Haploid cells
- Hare lynx
- Venn diagram asexual vs sexual reproduction
- The disadvantages of sexual reproduction
- Sexual reproduction and genetics section 1 meiosis
- Section 1 meiosis
- Chapter 8 cellular reproduction cells from cells
- Diploid to haploid meiosis
- Homologous chromosome vs sister chromatid
- Haploid cells def
- Produces haploid cells
- Anaphase in meiosis vs mitosis
- Sexual reproduction
- Chapter 20 sexual reproduction in animals
- Chapter 10 sexual reproduction and genetics