The Cell Cycle Interphase , Mitosis, and Cytokinesis

1. The Cell CycleInterphase, Mitosis, and Cytokinesis 10-2

2. Learning Goals • 1. Summarize the cell cycle and what it results in. • 2. Describe the function of the cell cycle in both a unicellular and multicellular organism. • 3. Define chromosome and describe its parts. • 4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.

3. Cell Cycle • Cell Cycle - cell division that results in 2 new daughter cells that are an exact copy of the original (parent) cell.

4. The Cell Cycle • Three Main Stages: • a) Interphase (95%) • b) Mitosis (5%) • c) Cytokinesis M Phase M phase = cell division

5. Function • Unicellular organisms reproduce this way (asexual reproduction) • Multicellular organisms make new cells this way • Causes organisms to grow • To replace old worn out cells • Repair damaged cells

6. Chromosomes • Carry genetic information • DNA = genetic code • Every organism has a different # of chromosomes • ex: humans have 46 (23 from mom & 23 from dad)

7. One chromosome = pair of sister chromatids • Sister Chromatid= 1 copy of wound up DNA • Sister chromatids are held together by a centromere centromere Sister chromatid Sister chromatid

9. Interphaseoccurs before mitosis begins • Chromosomes, cytoplasm, and organelles are copied. • The cell grows

10. Mitosis

11. Prophase1st step in Mitosis • The genetic material (DNA) condensesinto bundles called chromosomes.

12. Nuclear membrane disappears • Spindle fibers form • Centriolesmove to opposite sides of the cell

13. Metaphase2nd step in Mitosis • The chromosomesline up along the middle of the cell

14. Spindle fibers attach to the centromeresof chromosomes

15. 4.Anaphase3rd step in Mitosis • Sister chromatids separate and move toopposite sides of the cell

17. Telophase4th step in Mitosis • Nuclear membrane forms around each set of chromosomes

18. Chromosomes unwind into chromatin • Spindle fibers disappear

19. Now you try! • Identify the 4 steps of mitosis on the next slide (Hint: They are not in order)

20. Telophase Prophase Metaphase Anaphase

21. Cytokinesisoccurs after mitosis • The cytoplasm splits in two • Result is two identical cellsthat have thesame number of chromosomesas the original cell.

25. Learning Goals • 1. Summarize the cell cycle and what it results in. • 2. Describe the function of the cell cycle in both a unicellular and multicellular organism. • 3. Define chromosome and describe its parts. • 4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.