Mitosis and Cytokinesis

1. Mitosis and Cytokinesis Animated Mitosis

2. Mitosis • During mitosis, the cells’ copied genetic material separates and the cell prepares to split into two cells • This allows the cell’s genetic material to pass into the new cells • The resulting daughter cells are genetically identical!!

3. Where Do I Find DNA? • Chromosomes are in the nucleus of every cell. • Chromosomes are made up of DNA. • Genes are pieces of DNA that contain the instructions for building a protein.

4. Sister Chromatids & Chromosomes Human somatic cells (any cell other than a gamete) have 23 pairs of chromosomes. – one from mom and one from dad. These are called homologous chromosomes. Copy of chromosome from mom or dad Chromosome made in S phase of Interphase

5. The Four Stages of Mitosis • Remember PMAT! • Prophase • Metaphase • Anaphase • Telophase

6. Prophase • The cell’s chromatincondenses into chromosomes • The chromosomes look like an “X” • Each chromosome is made up of two identical sister chromatids attached by acentromere • This is “created” in S phase of interphase

7. Chromosome Structure Humans have 23 pairs of chromosomes.

8. Prophase Continued • Nucleus disappears • Spindle fibers form in the cytoplasm • Spindle fibers attach to sister chromatids

9. Metaphase • The sister chromatids are pulled to the center of the cell • They line up in the middle of the cell

10. Anaphase • Spindle fibers begin to shorten • The sister chromatids are pulled to the opposite ends of the cell

11. Telophase • The sister chromatids arrive at the opposite poles of the cell and begin to unravel • New nucleus begins to form

12. Cytokinesis • Cytokinesis is the division of the cytoplasm • Results in two separate cells with identical nuclei • In animal cells, it is accomplished by using microfilaments to “pinch” the cytoplasm Cytokinesis in an Animal Cell

13. Cytokinesis in a Plant Cell In plants, a cell plate forms between the two daughter nuclei

14. Real-Life Cells Dividing! Animated Mitosis