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Mitosis. Ms. Napolitano & Mrs. Haas CP Biology. Recall: The Cell Cycle. Interphase: cell growth G 1 , S, & G 2 phases combined M Phase: cell division Mitosis – division of the nucleus Cytokinesis – division of the cytoplasm. Mitosis. Mitosis = asexual reproduction
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Mitosis Ms. Napolitano & Mrs. Haas CP Biology
Recall: The Cell Cycle • Interphase: cell growth • G1, S, & G2 phases combined • M Phase: cell division • Mitosis – division of the nucleus • Cytokinesis – division of the cytoplasm
Mitosis • Mitosis = asexual reproduction • Makes identical clones • 1 cell = 2 daughter cells Original cell Daughter cells
Chromosomes • Chromosomes – carries genetic information • Made of DNA & proteins • All organisms have a specific number • Fruit flies = 8 • Carrots = 18 • Humans = 46 • Not visible until cell division • Made of two sister chromatids attached at the centromere
Chromosome Number • Human body cells (not sex cells) are diploid • One set from mom, one set from dad! • Humans: 2n = 46 • 23 SETS of chromosomes, 46 total
Stages of mitosis • 4 Stages: • Prophase • Metaphase • Anaphase • Telophase *Don’t forget Mitosis is followed by cytokinesis!
Prophase • Longest phase • Chromosomes become visible • DNA originally chromatin – mass of DNA • Centrioles move to opposite sides of the cell • Spindle fibers form (microtubules) • Nuclear membrane breaks down • Nucleolus disappears
Metaphase • Chromosomes line up at the center of the cell • Microtubules attach to the centromeres of chromosomes
Anaphase • Sister chromatids separate • Now become individual chromosomes – confusing, I know! • Move towards opposite poles
Telophase • Chromosomes de-condense • Back to chromatin! • Nuclear envelope reforms • Spindle fibers break • Nucleolus reappears
Cytokinesis • After mitosis – 2 nuclei in one cell • Cytokinesis divides the cytoplasm • Makes 2 completely different cells • May occur with telophase • Animal cells: membrane drawn in, pinches off • Cleavage furrow formed • Plant cells: cell plate forms between nuclei Cell plate Plant cell Animal cell Animal cell
Video http://app.discoveryeducation.com/search?Ntt=mitosis (This is so cheesy but I think it’s really helpful!)