3. The cell cycle has four main stages The cell cycle is a regular pattern of growth, DNA replication, and cell division.

4. The main stages of the cell cycle are gap 1, synthesis, gap 2, and mitosis –Gap 1 (G 1 ): cell growth and normal functions Important: Mitosis occurs only if the cell is large enough and the DNA undamaged. –DNA synthesis (S): copies DNA –Gap 2 (G 2 ): additional growth –Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis)

5. What is Mitosis? Mitosis: Cell division involving somatic (non- sex) cells Involves only diploid cells Form of asexual reproduction for some life (bacteria & protista, fungi) End Result: Two genetically identical “daughter cells”

6. Interphase Divided into 3 Stages: G1 Stage –Normal function performed –Cell growth –Organelles created S Stage –Chromatin (DNA strands) duplicated G2 Stage –Cell growth –Normal function performed

7. Prophase 1 st Mitosis Stage Chromatin (DNA strands) coils into chromosomes Nucleus dissolves spilling the chromosomes Spindle fibers form

8. Metaphase 2 nd stage of mitosis Spindle fibers attach to centromeres of each chromosome Spindle fibers pull the chromosomes to the cell’s equator

9. Anaphase 3 rd stage of mitosis Spindle fibers pull ½ the chromatids to each end of the cell –Humans: 46 chromatids each way

10. Telophase 4 th stage of mitosis Spindle fibers dissolve Chromatids unwind into chromatin Nucleus reforms Cytokinesis: division of the cytoplasm

13. Name that Stage!

20. Quick Review Mitosis = the division of somatic (non- sex) cells Each stage has different characteristics End Result = Two identical diploid cells