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Mitosis

Mitosis. Cell Division. Cell division is the cornerstone of life. Genome : a cell’s complete set of an Organism’s genetic material comprised of (DNA). Chromosomes . Prokaryotes have a single, circular chromosome. Cell Division. Prokaryotes (bacteria) reproduce through cell division.

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Mitosis

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  1. Mitosis

  2. Cell Division Cell division is the cornerstone of life Genome: a cell’s complete set of an Organism’s genetic material comprised of (DNA)

  3. Chromosomes Prokaryotes have a single, circular chromosome

  4. Cell Division • Prokaryotes (bacteria) reproduce • through cell division Binary fission • Circular chromosome • (DNA) is replicated New cell wall forms between copies, cell splits

  5. Mitosis • Eukaryotes use cell division to create new cells • MITOSIS: division of the nucleus Asexual cell division • Growth, Maintenance and Repair Mitosis Mitosis • Reproduction

  6. Chromosomes • Eukaryotes have genome distributed • across many chromosomes • Humans: 46 (23 pairs) • Mosquito: 6 (3 pairs) Toad: 22 (11 pairs) • Potato: 48 (24 pairs) Dog: 78 (39 pairs)

  7. Chromosome made of a DNA & protein complex: chromatin Following DNA replication, a chromosome contains Two sister chromatids attached by a centromere Chromosome Sister Chromatids Centromere

  8. Humans: 46 • 2 sets of 23 chromosomes (diploid) • n = number of chromosomes in a set • Fundamental number, haploid number • n = contribution from each parent • 46 chromosomes (2n = 46) 23 = 1 sex chromosome, 22 autosomes

  9. Mitosis and Interphase Alternate • The cell cycle • Cells are in interphase 90% of the time • G1 = Gap 1 (cell growth) • S = chromosome synthesis (duplication) • G2 = Gap 2 (cell growth) • M = Mitosis

  10. Mitosis and Interphase Alternate Parent cell is Homologous (2n, diploid) Chromosomes are replicated during S-phase of cell cycle. Chromosomes and copies are separated during mitosis. One of each pair to daughter cell Copies

  11. Stages of Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokenesis

  12. Prophase • Chromatin coils into visible chromosomes • Under a light microscope, only the nuclear envelope (with nucleoli) and a tangle of chromatin are visible • Centrosomes: mitotic centers, poles for division

  13. Metaphase • Nuclear envelope breaks • Microtubules attach centromere to centrioles (in mitotic center aka centrosome) • Chromatids align on a plane at cell’s equator

  14. Anaphase • Chromatids separate simultaneously • Sister chromatids become daughter chromosomes

  15. Telophase • Daughter chromosomes stop moving • Chromosomes uncoil, nucleus and nucleoli reform

  16. Cytokinesis • Mitosis: nuclear division (karyokinesis) • Division of cell cytoplasm after mitosis is known as cytokinesis • Cell membrane/wall forms creating two new cells

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