1. “Cell division is part of the cell cycle” SECTION 3.2 & 3.3

2. Do Now!!  Label the following diagram:  1- chromosome  2- chromatid  3- centromere

3. Objectives  To identify the steps of mitosis  To define interphase  To build a cell cycle model using paper plates

4. The Cell Cycle  The normal sequence of development and division of a cell  Two main phases: Interphase & M-phase (Mitosis)

5. Interphase There is no division in interphase, just growth. G 1 : organelles duplicate, cell grows S: DNA replicates (is copied) G 2 : cell grows, prepares to divide

6. M-phase (Mitosis)  Mitosis: cellular division!  PMAT+ C  Prophase  Metaphase  Anaphase  Telophase  Cytokinesis

8. Mitosis  Creates 2 genetically IDENTICAL daughter cells.

9. Prophase  DNA condenses to form chromosomes.  Each chromosome has 2 chromatids and a centromere  The nuclear membrane disappears

10. Metaphase – “Middle”  Chromosomes line up in the middle of the cell at the “equator”

11. Anaphase – “away”  Chromatids split  Spindles pull to opposite sides of the cell AWAY from each other

12. Telophase  2 Nuclei form  Nuclear membrane forms around each group of chromosomes.  The chromosomes become chromatin again.

13. Cytokinesis  Division of the cytoplasm.  Occurs differently in plant and animal cells  2 new daughter cells!

14. Do Now!!  What are the 2 main phases of the cell cycle?  What are the stages of mitosis?  In which stage do the chromosomes line up in the middle?

15. Objectives  To compare and contrast cytokinesis in plant and animal cells  To illustrate and label the stages of mitosis!

16. Cytokinesis  Animal Cells:  Membrane pinches together and forms a cleavage furrow until the cells separate.

17. Cytokinesis  Plant Cells:  Cell plate forms which becomes the cell wall and divides the two cells.

18. Both sexual and asexual reproduction involve cell division  Most unicellular organisms use cell division to reproduce  Called asexual reproduction- one organism produces one or more new identical organisms  Live independently of parent  Ex: new skin cells are part of skin tissue and cannot live independently!

19. Asexual reproduction: Binary Fission  A form of asexual reproduction in prokaryotes  The parent organism splits in two, creating two new daughter cells  Genetically all the same!

20. Asexual Reproduction: Budding  Tiny buds on organisms body  Genetic material the same!  Detaches when it reaches a certain size  Both unicellular and multicellular can reproduce by budding  Ex: unicellular- some yeast multicellular- Hydra Hydra

21. Asexual Reproduction: Regeneration o The process of new tissue growth at sites with wounds or lost limbs. Newt Starfish Mexican Axolotl

22. Bacteria o Many bacteria have a very short generation time o Some can have a new generation of cells in less than 30 min o Ex: E. Coli can double every 20 minutes **Why you get sick so fast! E. Coli