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Mitosis Meiosis + Mitosis + Learning Outcomes Explain the functions of mitosis. Describe the basic features of the Cell Cycle. Distinguish between interphase, mitosis, and cytokinesis. Describe the chromosomes movements in mitosis (prophase, metaphase, anaphase, telophase) Distinguish between cytokinesis in plant and animal cells. Cell Division -- why bother? It’s how organisms reproduce It’s how organisms grow Daughter cells Purpose – provide one or more copies of the genome to each daughter cell Functions of Mitosis Replacement of Cells Functions of Mitosis Growth Functions of Mitosis Regeneration Functions of Mitosis Asexual Reproduction In modern agriculture, many plants are propagated asexually Fruit and nut trees are grafted Potatoes are grown from “eyes” of the potato (and there are many other examples) The Cell Cycle G1 cytoplasmic division telophase anaphase metaphase prophase mitosis S G2 Some terminology Diploid – containing two copies of the genome per cell Haploid - containing one copy of the genome per cell Gametes – cells that are the haploid cells combined during fertilization Overview of the Cell Cycle Diploid Cell with unduplicated chromosomes Diploid Cell after chromosomes have duplicated After mitosis, the daughter cells have the same set of chromosomes as the parent cell. Interphase Chromosomes are loosely packed so that the DNA can be used For mitosis, chromosomes are packaged into extremely condensed structures Chromosomes Chromosomal DNA molecules Sister chromatids Chromosome duplication Centromere Sister chromatids Separation of sister chromatids and distribution into two daughter cells Human Karyotype The human genome contains 23 pairs of chromosomes. 2 N = 46 genome size – 3.4 x 109 nucleotides coding for ~20,000 genes Phases of Mitosis Prophase Phases of Mitosis Metaphase Phases of Mitosis Anaphase Phases of Mitosis Telophase & Cytokinesis Cytokinesis Plant cells – vesicles containing cell wall components aggregate at the center of the cell and fuse. Animal cells – actin and myosin form a contractile ring and pinch the two cells apart. Mitosis starts with a diploid cell and produces two diploid daughter cells The Cell Cycle G1 cytoplasmic division telophase anaphase metaphase prophase mitosis S G2 Cancer & The Cell Cycle in normal cells --- signal to divide G1 cytoplasmic division telophase anaphase metaphase prophase mitosis S G2 In cancer cells – these check-points are lost signal to undergo cell suicide Cancer, Henrietta Lacks & Tissue Harvesting
