1. CELL DIVISION Life Science

2. How do little elephants grow up to be BIG elephants?

3. WHY DO ANIMALS SHED THEIR SKIN?

4. CELL DIVISION Cell division: increases the number of cells and causes many- celled organisms to grow.  The new cells that are formed are called: daughter cells Life cycles: periods of formation, growth and development Nucleus: control center of the cell. Contains DNA  DNA makes up a Chromosome

5. genes

6. 1) Reproduction 2) Growth 3) Repair Why do cells divide? How does the cell know how to divide? The DNA has the instructions for all of the cell’s activities.

7. 1.Interphase - Preparation 2.Mitosis – Cell division 3.Cytokinesis – Splitting  Adult human cell: ~24 hrs 18-20 hours in interphase 2 hours in mitosis 3 Parts How long does it take? The sequence of development and division of a cell

8. Animated Cell Cycle http://www.cellsalive.com/mitosis.htm Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

9. StageDefinitionPictureDiagram 1.Interphase (I) NOT part of mitosis -chromosomes replicates -cell grows + rests

10. INTERPHASE Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

11. StageDefinitionPictureDiagram 1.Interphase (I) NOT Part of mitosis -Chromosomes replicate -cell grows + rests 2. Prophase (Play) -nuclear membrane and nucleolus disappears -spindle fibers start to form from centrioles CentromereChromosome CentrioleSpindle Fiber

12. PROPHASE Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Spindle fibers Chromosome

13. 3. Metaphase (More) -double chromosomes attach to spindle -line up at equator (middle) Spindle Chromosomes Centriole Spindle

14. METAPHASE Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

15. 3. Metaphase (More) -double chromosomes attach to spindle -line up at equator (middle) 4. Anaphase (At) -chromosomes separate towards ends of cell Chromatid Spindle Centriole

16. ANAPHASE Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

17. 3. Metaphase (More) -double chromosomes attach to spindle -line up at equator (middle) 4. Anaphase (At) -chromosomes separate towards ends of cell 5. Telophase (The) -chromosomes reach opposite sides -cytoplasm divides (cytokinesis) (Circus) Cell Plate Chromosomes Cleavage Furrow Nuclear Membrane

18. TELOPHASE Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

19. REMEMBER! I Interphase P Prophase M Metaphase A Anaphase T Telophase C Cytokinesis IPMATC I Play M ore At T he Circus

20. BUT WHY DO CELLS DO THIS?

21. RESULTS OF MITOSIS 1.Produces two identical daughter cells 2.Daughter cells will have exactly the same number of chromosomes as the parent cell Ex. Human body cells have 46 chromosomes 3.This is a form of asexual reproduction

22. PLANT CELL MITOSIS VS ANIMAL CELL MITOSIS Plant cell MitosisAnimal Cell Mitosis Cytokinesis (cytoplasm divides) Centrioles (spindle) Cleavage furrow Cell plate

23. PLANT CELL MITOSIS VS ANIMAL CELL MITOSIS Plant cell MitosisAnimal Cell Mitosis Cytokinesis (cytoplasm divides) Cell plateCleavage furrow Centrioles (spindle) Cleavage furrow Cell plate

24. PLANT CELL MITOSIS VS ANIMAL CELL MITOSIS Plant cell MitosisAnimal Cell Mitosis Cytokinesis (cytoplasm divides) Cell plateCleavage furrow Centrioles (spindle) Not presentPresent + asters Cleavage furrow Cell plate

25. CANCER Cancer is uncontrolled cell division/cell growth Factors damaging genes that may lead to cancer: 1. Ultraviolet (UV) radiation 2. Chemicals/pollutants 3. Airborne particles (asbestos) 4. Diet 5. Radioactivity

26. ASEXUAL REPRODUCTION Asexual Reproduction:  Forms new organisms  Involves one parent  Genetic information identical to parent Ex. If mom has 12 chromosomes, baby has 12 chromosomes

27. BENEFITS: DISADVANTAGES:

28. MethodDefinitionExamples Binary Fission Parent cell divides into 2 equal size daughter Cells http://www.youtu be.com/watch?v= 3cD3U2pgb5w Amoeba Euglena Bacteria

29. MethodDefinitionExamples Binary Fission Parent cell divides into 2 equal size daughter cells Amoeba Euglena Budding Parent cell divides into 2 unequal size daughter cells http://www.youtube.com /watch?v=JZLHJZZZS-Y Yeast Hydra Bacteria Hydra

30. MethodDefinitionExample Sporulation http://www.youtube.co m/watch?v=OrKr QI8Grb0 1,000’s of specialized cells that burst from a spore case Bread Mold Mushroom

31. MethodDefinitionExample Sporulation 1,000’s of specialized cells that burst from a spore case Bread Mold Regeneration http://www.youtube.com /watch?v=f7cXeWxxfD4 Ability to re- grow body Parts -some re-grow parts -some re-grow new organisms Parts- Salamander/ lizard tail, lobster claws, starfish legs Whole Organism- Planaria Starfish from one leg and part of eye Mushroom

32. MethodDefinitionNaturalArtificial Vegetative Propagation Asexual reproduction in plants involves roots, stems, and leaves Natural and Artificial a.Tuber-white potatoes b. Bulb-tulip c. Runner- strawberry d. Rhizome-iris e. Grafting-apples f. Layering- raspberries g. Cutting-spider plant

33. MEIOSIS: SEXUAL REPRODUCTION  Formation of sex cells: sperm and egg  Sex cells have half the number of parent cells Ex. In humans sex cells have 23 chromosomes not 46 like all the other cells Why? 2 divisions  4 cells are produced

34. BENEFITS: DISADVANTAGES:

35. Parent Cell 1 st Division MEIOSIS – TWO DIVISIONS OF THE NUCLEUS 2 nd Division – 4 new daughter cells with ½ the # of chromosomes

36. FERTILIZATION Fertilization: the joining of an egg and a sperm from 2 different organisms of the same species  The cell that forms from fertilization is called the zygote.  Fertilization restores the number back to 46.