1. Chapter 5: Mitosis is the basis of Asexual Reproduction

2. Cellular Reproduction How do we change from 2 cells into trillions?...37.2 trillion actually….

3. How much is a trillion anyway….

4. Or a trillion pennies…..

6. How do you regenerate your body parts?

7. What is cancer?

8. Some Important Genetic Facts Human body cells have 46 chromosomes each. These chromosomes are grouped into 23 pairs (2 x 23 = 46!) Each pair of chromosomes contains the same kinds of genes, but one chromosome came from your father and one from your mother, so they are slightly different.

10. The Cell Cycle Cells, and therefore your body parts, reproduce through a continuous process of growth and division called the cell cycle. This cycle consists of two main stages: 1. The growth stage (Interphase) 2. The division stage (Mitosis)

11. The Cell Cycle Cell gets bigger Produces important proteins for cell functions DNA is copied so each new cell will have the same DNA Cell keeps growing Organelles are duplicated! One cell divides into two identical cells (unless errors occur!) Growth and preparation DNA replication Continued growth and preparation Mitosis Cytokinesis The splitting of cell membranes

12. Cell Cycle & Development It is necessary for cells to divide, producing more cells, as an organism develops. Cells die and need to be replaced. Cells that take a lot of wear and tear, including skin cells, stomach cells and intestinal cells need to be replaced frequently! The Cell Cycle ensures that body cells are replaced and the overall health of the organism is maintained.

13. Stages of the Cell Cycle Interphase: is the first and longest stage of the cell cycle. During this stage the cell carries out its various functions and prepares for division.

14. Stage 2: Mitosis Mitosis: the second, and usually the shortest stage of the cell cycle, involves the division of a cell’s nucleus and genetic material (chromosomes) producing two identical daughter cells.

15. Each daughter cell has the identical copies of the parent chromosomes. Each daughter cell has 46 chromosomes!

16. Phases of Mitosis It helps to understand mitosis by breaking it up into four different steps. However it is important to remember that these steps flow together with no beginning or end! The 4 stages of Mitosis, in order, are: 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase

17. Phases of Mitosis VIDEO 1 Video 2 (Amoeba Sisters) Video 3 (Hank)

18. Phase 1: Prophase During prophase the chromosomes shorten and thicken. The nuclear membrane that surrounded the nucleus breaks down and disappears.

19. Phase 2: Metaphase During metaphase chromosomes line up across the middle (or equator) of the cell.

20. Phase 3: Anaphase During anaphase chromosomes are pulled to opposite ends (poles) of the cell. The chromosomes are pulled at their centers.

21. Phase 4: Telophase At telophase, the sets of chromosomes that reached opposite poles form nuclei. They cell is now ready to divide into two identical daughter cells.

22. Cytokinesis Cytokinesis: is the final stage of the cell cycle. Once mitosis is complete, the cell membrane pinches together and the cell divides into two identical daughter cells.

23. Activity PMAT is an acronym that can help you remember the order of the stages of mitosis. P = prophase M = metaphase A = anaphase T = telophase With a partner, come up with a mnemonic device to help you remember what is happening during each phase. You do this by making up a word for each letter reminds you of what is going on in the cell!

24. Quick Term Review Traits Heredity DNA Chromosome Genes Mutations Mutagens Interphase Mitosis Prophase Metaphase Anaphase Telophase Cytokinesis Daughter cells

25. The products of Mitosis Mitosis results in one parent cell dividing to produce two identical daughter cells which have the same number of chromosomes as the parent cell. Think about it … How many brain cells originally underwent cell division to produce 24 brain cells? A cell divides by mitosis once every two hours. How many of these cells will be produced after an 8 hour period?

28. Checkpoints in the Cell Cycle (page 145) Special proteins at checkpoints monitor cell activities and send this information along to the nucleus. At each checkpoint, the nucleus instructs the cell whether or not to divide. A cell will stop undergoing division if: Not enough nutrients for cell growth Replication of DNA did not occur DNA is damaged