1 / 18

Chapter 13

Chapter 13. Meiosis & Sexual Life Cycles. Vocabulary. genome – an organism’s complement of DNA gene – segment of a chromosome that codes for one polypeptide asexual reproduction – a single individual gives rise to genetically identical offspring (clone)

rashad-fischer
Download Presentation

Chapter 13

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. Chapter 13 Meiosis & Sexual Life Cycles

  2. Vocabulary • genome – an organism’s complement of DNA • gene – segment of a chromosome that codes for one polypeptide • asexual reproduction – a single individual gives rise to genetically identical offspring (clone) • sexual reproduction – 2 parents give rise to offspring having DNA from each parent

  3. Human karyotype

  4. Vocabulary • somatic cell – body cell; not a sex cell • gamete – sex cell (egg or sperm) • diploid – a cell with 2 copies of the genetic material (2n) • haploid – (monoploid) a cell with one copy of the genetic material (1n)

  5. Vocabulary • autosomes – chromosomes other than sex chromosomes • sex chromosomes – X and Y usu. • zygote – cell created from the union of sex cells • fertilization (syngamy) – union of gametes • alternation of generations – alternating between diploid and haploid stages in the life cycle • sporophyte – diploid stage (2n) • gametophyte – haploid stage (1n)

  6. Meiosis • DNA replicates during interphase I prior to meiosis Meiosis I Prophase I – formation of 4-stranded groups (tetrads), DNA crossing over (synapse) between homologues occurs at chiasma, nuclear membrane, nucleolus breaks down, centrioles migrate to poles, spindle forms

  7. Meiosis Metaphase I - tetrads line up at equator Anaphase I– tetrads separate; homologues move to opposite poles Telophase I – nuclear membrane, nucleolus reappear, cytokinesis follows Meiotic interphase – no DNA replication

  8. Meiosis Meiosis II like mitosis Prophase II Metaphase II Anaphase II Telophase II

  9. Meiosis • Result: 4 haploid daughter cells through spermatogenesis or oogenesis (gametogenesis)

More Related