1. List the difference processes that can occur in a cell

2. Cell Growth and Division

3. 10.1 Cell Growth OBJ: Describe the importance of asexual cell division in growth, repair and maintenance of multicellular organisms

4. Limits to Cell Growth DNA Overload Membrane Transport and Homeostasis

5. Limits to Cell Growth: DNA “Overload” Small eukaryotic cell DNA is able to meet the needs to the cell.

6. Limits to Cell Growth: DNA “Overload” As the cell size increases, it does not make extra copies of DNA

7. Limits to Cell Growth: DNA “Overload” ◦In time, the cells DNA would no longer be able to serve the increasing needs of the growing cell.

8. Limits to Cell Growth: DNA “Overload” Think of a school population as it grows….

9. Limits to Cell Growth DNA Overload Membrane Transport and Homeostasis

10. Limits to Cell Growth: Exchange of Materials Necessary materials enter/leave the cell through the membrane

11. Limits to Cell Growth: Exchange of Materials The rate of this exchange depends on the surface area of the cell (the total area of the cell membrane)

12. Limits to Cell Growth: Exchange of Materials The rate of the use of the nutrients is determined by the volume of the cell

13. Volume to Surface Area Volume will always increase more rapidly than surface area If the cell were to get too large, it would begin to suffer

14. Volume to Surface Area Volume will always increase more rapidly than surface area If the cell were to get too large, it would begin to suffer difficult for oxygen, water, and nutrients to pass through the membrane at a rate that would sustain the increased volume inside

16. Division of the Cell Cell division Before becoming too large, the growing cell will divide creating two “daughter cells”

17. Division of the Cell Cell division Genetic Information must go through Replication each daughter cell one complete set Parent cells and daughter cells = exact same genetic information

18. Division of the Cell Cell division Cell volume decreased by this division each daughter cell now has increased surface area to volume to allow for sufficient material exchange

19. Ratio of Surface Area to Volume Boiled Egg Demo ◦Look at the amount of egg dyed after 10 minutes ◦What is the comparison of the whole egg to the cube of egg white? ◦How does this compare to the increase in surface area of a cell? ◦Why can a cell not continue to grow indefinitely?

20. 10.2 Cell Division

21. Cell Cycle OBJ: List the stages of the cell cycle and describe the events taking place at each stage

23. Chromosomes Genetic information in eukaryotes carried by chromosomes Number is specific to the organism Humans= 46, 23 pairs Fruit Flies= 8, 4 pair Cannot be seen in the cell except for during cell division

24. Chromosomes Before cell division, each single chromosome is copied Each structure is composed of sister chromatids (these split during division) Divide from the centromere (the center that holds them together)

25. Chromosome Structures

26. The Cell Cycle Cycle a cell grows prepares for division divides creating two daughter cells (identical to parent)

27. The Cell Cycle Interphase is the period of time where the cell is growing before division

28. Interphase Details Can be Very lengthy Most of the cells growth

29. Interphase Details creating new organelles and proteins Then chromosomes are replicated DNA is synthesized

30. Mitosis (Nucleus) and Cytokinesis OBJ: List stages of mitosis and describe the events taking place at each stage OBJ: Distinguish between mitosis and cytokinesis

31. Predict the Order!

32. Mitosis This stage in the cell cycle is divided into four parts ◦Prophase ◦Metaphase ◦Anaphase ◦Telophase http://sci.bio.lmu.de/epigenetics/cardosolab/pictures/research/cell-cycle-graphic- 1b.png

33. Prophase First/longest phase of mitosis Chromosomes become visible Nucleolus disappears and the nuclear envelop breaks down

34. Prophase The centrioles separate and move to opposite sides of the cell ◦ ( these help to organize the spindle for separating chromosomes) – these are only found in animal cells

35. Metaphase Second phase of mitosis The chromosomes are attached to the spindles The chromosomes lined up in the center of the cell

36. Metaphase Pictures

37. Anaphase Third phase of mitosis The centromeres that join the sister chromatids split and the chromatids become separate chromosomes

38. Anaphase These chromosomes move apart to the centrioles on opposite sides of the cell Phase ends when the chromosomes stop moving

39. Telophase Final phase of mitosis Nuclear envelope reappears around this genetic material

40. Telophase Spindles break apart and the nucleolus becomes visible in each new nucleus Mitosis is finished, but not cell division

41. Cell Division In eukaryotes, this occurs through mitosis (division of the nucleus) This is followed by cytokinesis (division of the cytoplasm) This allows for many organisms to reproduce asexually, or for more complex organisms to differentiate

42. Cytokinesis Two new nuclei are formed, and now the cytoplasm must divide Usually happens at the same time as telophase

43. Cytokinesis In most animal cells - the cytoplasm draw together in the center until it is pinched into two equal parts In plants, a cell plate develops in the middle of the cell ◦develops into a separating membrane, followed by a cell wall

44. Mitosis in a Cell Begins with one parent cell Ends with two daughter cells ◦Which are identical to the parent cell (full set of chromosomes)

45. Can you explain cell division very fast?

46. Cell Growth and Division Cell Growth and Division OBJ: Explain the results of uncontrolled cell division

47. Regulating the Cell Cycle Cells move through the cell cycle at different rates

48. Regulating the Cell Cycle In the human body: muscle cells and nerve cells do not divide at all once they have developed Skin, digestive and bone marrow cells do divide

49. Regulating the Cell Cycle This process provides new cells to replace those that are worn out (takes hours) Skin cells – sun burn / tan

50. Controls on Cell Division The controls for cell growth can be turned on and off ◦When cells come into contact with other cells, they respond by not growing

51. Controls on Cell Division The controls for cell growth can be turned on and off ◦When cells come into contact with other cells, they respond by not growing ◦Cells that are not touching another cell will continue to grow until they contact another cell  Examples: cuts and broken bones

52. Uncontrolled Cell Growth Cancer ◦a disorder in which the body’s cells lose the ability to control growth

53. Uncontrolled Cell Growth Cancer cells do not respond to the signals that regulate the growth of most cells ◦causes them to grow uncontrollably ◦develop a mass of cells (tumors) that can damage surrounding cells

54. Uncontrolled Cell Growth These cells can break loose of the mass and travel throughout the body

55. Causes of Uncontrolled Growth Environmental factors and Hereditary factors All have one thing in common – control over the cell cycle has broken down

56. NIH Cancer Lesson Plan http://science.education.nih.gov/supplements/nih1/Cancer/activities /activity2_videos.htm

57. Cancer Skits Biomedical Cancer videos Answer the questions while/after watching each skit Class Discussion

58. Unit Objectives Describe the importance of asexual cell division in growth, repair, and maintenance of multicellular organisms. List stages of the cell cycle and describe the events taking place at each stage. distinguish between mitosis and cytokensis (cell division) list the stages of mitosis and describe the events taking place at each stage explain the results of uncontrolled cell division (cancer)