3.  How many cells do we have in our bodies?  Approx. 100 trillion cells!! WOWZA!  What would happen if our arms and/or legs consisted of just one giant cell and that cell stopped working or died?  We wouldn’t have a working limb, or it may fall off!

4.  What do we do if our cells die or get damaged?  Buy some on ebay? Amazon.ca?  Nope, we let this process called mitosis do its thing  So why do we need Mitosis?  To fill the space left by dead cells (cell reproduction), to help cells grow (cell growth), and to pass on cell DNA

5.  Well......?  Yes, you’re right!  It is an asexual cellular division that produces two identical daughter cells  How does this exciting process happen?  Right again!  It begins with a process called interphase  Followed by Mitosis  Finally following mitosis cytokinesis occurs

6.  G0  Non-dividing stage  G1 (Gap 1):  Produce RNA  Synthesis protein  S Phase  DNA replicates  One sister chromosome becomes two sister chromatids  G2 (Gap 2):  Cells prepare for mitosis

7. Prophase Metaphase http://www.youtube.com/watch?v=C6hn3sA0ip0 Anaphase Telophase

8. What characteristics are present, when prophase begins? 1. Individual condensed chromosomes become visible 2. Condensation continues through prophase 3. Nucleolus disappears

9.  Assembling the Spindle Apparatus  Microtubule apparatus made of spindle fibers continues to assemble  Animal cells form an arrangement called an aster  Linking sister chromatids to opposite poles  Second group of microtubules grow out from centromeres to poles  Sister chromatids won’t separate if both connected to same pole

10. Key Characteristics of Metaphase. 1. Stage begins when chromosomes align in center of the cell 2. Alignment occurs along the metaphase plate a. Not a physical structure b. Indicates where future axis of cell division occurs 3. Centromeres are equidistant from each pole

11.  Centromeres divide at the end of metaphase  Centromere splits in two, freeing sister chromatids from one another  Spindle fibres attach to the kinetochore, which controls/supervises movements of chromosomes during cell division  All centromeres divide in synchrony

12.  Is the shortest phase, during which sister chromatids separate  Chromatid drawn to pole to which its kinetochore is attached  Separation achieved by two simultaneous microtubular actions  Poles move apart  Centromeres move toward poles

13.  Separation of chromatids Completes partitioning of replicating genome  Spindle apparatus is disassembled  Tubulin units of microtubules are used to build new cytoskeleton  Nuclear envelope re-forms around each new set of chromosomes  Chromosomes begin to uncoil to allow gene expression  Nucleolus reappears

15.  Mitosis complete at end of telophase  Replicated genome divided into two nuclei at opposite ends of cell  Cytoplasmic organelles assort to regions that will become separated  Cleavage of the cell into two halves constitutes cytokinesis  Cytokinesis in animal cells  Cell is pinched in two by a constricting belt of microfilaments  Actin filaments slide past one another  Produces distinct cleavage furrow around circumference of cell  Furrow deepens until the cell is pinched in two