Mitosis- A Story of Cell Division http://www.cellsalive. com/mitosis.htm Remember the characteristics of living things? Hmmm?? • 1) Made up of cells • 2) Grow and Develop • 3) Respond to their Environment • 4) Obtain and use Energy • 5) Reproduce • 6) DNA • 7) Evolve over time • 8) Maintain homeostasis Cell Division occurs in ALL living organisms! •But why??? •Because in order for anything to grow- cells must divide to make more… •Skin cells, Red Blood Cells, Plants cells, Wounds healing... The Cell Cycle •Life presents many cycles… •Cells are in either in an active dividing stage or are resting (not actively dividing) https://www.youtube.com/w atch?v=Wy3N5NCZBHQ The Parts of the Cell involved in Mitosis •Cell membrane •Nucleus •Nucleolus •Nuclear membrane •Chromosomes •Centrioles •Spindle Fibers Chromosomes •Chromosomes- strands of DNA (genetic material) containing protein. A- chromosome B- centromere C- sister chromatid •Organisms have different numbers. Humans have 46. Fruit flies have 8 ! Interphase (G1 phase) •Inter = between •Interphase- Nucleolus is generally seen (dark purple circle). Chromosomes cannot actively be seen- but chromosomes (DNA) and centrioles are dividing. 4 Active Phases of Mitosis (M phase) •1) Prophase(like before) Before the other stages… •Chromosomes visible, Centrioles begin to move to ends of the cell, Spindle fibers begin to form. Metaphase •Meta= middle •Chromosomes meet in the middle, and line up along the center of the cell. Anaphase •Chromosomes have replicated (doubled) and now will split apart to either sides of the cell (sister chromatids) •Ana = (arms out) Telophase •Centrioles, and Spindle fibers start to disappear. Chromosomes are at opposite sides of cell. New nuclear membrane forms. Looks like two cells ! Cytokinesis • Dividing of the cytoplasm Results of Mitosis •1) Mitosis is the division of the nucleus •2) Mitosis results in the same number of chromosomes that were in the original cell