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You started as a cell smaller than a period at the end of a sentence… .

You started as a cell smaller than a period at the end of a sentence… . And now look at you! How did you get from there to here?. Why do cells divide again?. Reproduction Growth & Development Repair & Replacement. Phases of Mitosis. Overview of Mitosis (I.P.M.A.T.). Prophase.

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You started as a cell smaller than a period at the end of a sentence… .

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  1. You started as a cell smaller than a period at the end of a sentence… . And now look at you! How did you get from there to here?

  2. Why do cells divide again? • Reproduction • Growth & Development • Repair & Replacement

  3. Phases of Mitosis

  4. Overview of Mitosis (I.P.M.A.T.)

  5. Prophase • Longest phase in mitosis (takes 50-60% of total time mitosis requires) • Chromosomes become visible, because they are condensed.

  6. Prophase 2. Centrioles move to opposite ends of the cell. 3. Spindle fibers form between centrioles. 4. The nucleolus disappears & the nuclear envelope breaks down.

  7. Metaphase • Chromosomes line up in the center of the cell. • Spindle fibers attach to the centromere of each chromosome.

  8. Anaphase • Sister chromatids separate from each other & are pulled to opposite ends of the cell. • Anaphase ends when the chromosomes stop moving.

  9. Telophase • Chromosomes look like threads (chromatin) again. • A nuclear envelope forms around each cluster of chromosomes. • Spindle breaks apart This is the end of mitosis, but NOT the end of cell division!

  10. Mitosis End Result • In Eukaryotes, the nucleus is divided into 2 separate nuclei. • Mitosis conserves the number of chromosomes & equally allocates the replicated chromosomes into each of the daughter nuclei.

  11. Cytokinesis – NOT part of mitosis! • Cell division is not complete until the cytoplasm divides! • In plants, a cell plate forms between the 2 daughter nuclei. The cell plate develops into a cell membrane & cell wall.

  12. Cytokinesis • In animal cells, the cell membrane is drawn inward until the cytoplasm is pinched into 2 equal parts. • Each part has a nucleus & organelles.

  13. IPee More After Tea Constantly Idiotic Penguins Make Antarctica Too Cold Intergalactic Plasma Man Abducted The Captain

  14. Chromosomes • Humans have 46 chromosomes per cell. • Half of your chromosomes come from your mother & half come from your father!

  15. Homologous Chromosomes • 2 chromosomes that contain genes for the same biological features (like eye color) at the same locations on the chromosome • Each pair can contain the same trait (both code for blue eyes) or different traits (1 codes for blue & 1 codes for brown) for each feature.

  16. One of the chromosomes in each homologous pair came from your mother & one came from your father!

  17. Diploid Cells (2n) • Contain both sets of homologous chromosomes (called 2n) All somatic (body) cells are diploid! In humans, all somatic cells have 46 total chromosomes, which is 23 homologous pairs!

  18. Haploid Cells (1n) • Contain only 1 copy of each chromosome (called n) • In humans, n=23

  19. Haploid Cells (1n) • Gametes (sperm & egg cells) are haploid! • When 1 sperm & 1 egg combine their DNA, they form a zygote with 2 versions of each chromosome.

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