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Bellringer

Bellringer. Pg. 56 in your book “My Planet Diary” Read and answer the questions. Be ready to discuss in 5 minutes. Cell Division. Chapter 2 Lesson 3. Why Do Cells Divide?. Cells divide for three reasons Growth Adding new cells to get bigger Repair Fixing broken cells Maintenance

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Bellringer

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  1. Bellringer • Pg. 56 in your book “My Planet Diary” • Read and answer the questions. • Be ready to discuss in 5 minutes

  2. Cell Division Chapter 2 Lesson 3

  3. Why Do Cells Divide? • Cells divide for three reasons • Growth • Adding new cells to get bigger • Repair • Fixing broken cells • Maintenance • Replacing old cells • Some cells divide to reproduce • Unicellular organisms • Plant structures can break away and become a new plant

  4. The Cell Cycle • Regular sequence of growth and division in cells • Life cycle of the Cell has three parts • Interphase • Growth before cell division • Mitosis • Division of the Nucleus • Cytokinesis • Division of the cytoplasm

  5. Interphase • Where a cell spends most of its life • G1-Growth • Grows to its full size and produces organelles • S-Synthesis (Replication) • DNA (chromatin) is copied • Chromatin-uncoiled DNA in the nucleus • G2-Preparation for Division • Cell produces structures that will help it divide

  6. Mitosis

  7. Mitosis-Prophase • Longest phase of mitosis • Chromosomes form • Chromosomes-rod-like structures formed from DNA and proteins • Nuclear envelope disappears

  8. Mitosis-Metaphase • Spindle fibers attach to centromere • Holds chromatids together • Chromosomes are lined up at metaphase plate

  9. Mitosis-Anaphase • Sister chromatids are pulled to opposite sides of the cell • Chromatids-exact copies of DNA attached at centromere

  10. Mitosis-Telophase • Nuclear envelope reforms • Chromosomes uncoil • Happens simultaneously with cytokinesis

  11. Cytokinesis in Plant and Animal Cells • Cytokinesis • Division of the CYTOPLASM • Animal Cells • Form a cleavage furrow and cytoplasm pinches to form two daughter cells • Plant Cells • Form a cell plate which breaks to form two daughter cells

  12. Mitosis

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