1. Cell Growth and Division
Chapter 10

2. Why would we need new cells???

3. Growth
Repair
Cell death

4. Does cell size Matter?
Comparison of cells to everyday items we see with our eyes with ones that need a microscope.
Write down two observations or reactions to the cell size comparisons.

5. Which type of cell is more efficient?
Why?

6. Limits of cell growth Why cells stay small…and divide DNA Overload
Larger cells mean more demand of DNA
Exchange of material
Surface area affects exchange rate
Surface area
Volume increase more than surface area

8. Before the cell becomes too large, it divides into two “daughter” cells in a process called Cell Division

9. Cell division

10. How is prokaryotic and eukaryotic cell division different?

11. Cell Division
Prokaryotes
Binary Fission
Eukaryotes
Mitosis
Meiosis

12. Cell Cycle
Series of events that that cells go through as they grow and divide

13. 3 parts of the cell cycle:
Interphase
Mitosis
Cytokinesis

14. INTERPHASE- 3 phase G1 phase Monitor environment and cell size
Checks for DNA damage
grows
Organelles prep for cell division
Cell spends most of its life in Interphase

15. S phase
DNA is copied

16. G2 phase Intracellular components replicated
Last chance for growth prior to division

17. Mitosis
Division of the nuclear material
4 phases

18. Cytokinesis
Division of the cytoplasm

19. Internet activity
Cell Plate activity

21. Mitosis animation

22. Chromosomes Compact, coiled DNA Sister Chromatids Centromere
One half of the chromosome
Centromere
Between the two chromatids
holds them together

23. Mitosis How all cells divide EXCEPT reproductive cells
The cytoplasm and nucleus both divide
Results in two cells that are genetically identical

24. Prophase DNA is shortened and tightened into chromosomes
Nucleolus & nuclear membrane break down & disappear
Two centrosomes appear
Spindle fibers appear

25. Metaphase
Spindle fibers move chromosomes to the center of cell

26. Anaphase
Chromatids separate at the centromere and are pulled to opposite poles of cell by spindle fibers

27. Telophase Spindle fibers break down Chromosome loosens up
Nuclear envelope forms around each set of chromosomes
Nucleolus forms

28. Cytokinesis

29. Cytokinesis-in animals
Cell membrane pinches inward creating a cleavage furrow
Eventually leads to two cells

30. Cell Plate
Only in plants
Cell plate forms between two nuclei

32. Mitosis/cell cycle Video

33. Regulation of the cell cycle

34. Not all cells divide at the same time
Cell type
Life span
Esophagus
2-3 days can divide
Small intestine
1-2 days can divide
Large intestine
6 days can divide
Red blood cells
<120 days cannot divide
White blood cells
0 hrs – decades many do not divide
Smooth muscle
Long lived can divide
Heart muscle
Long lived cannot divide
Nerve cells
Long lived most do not divide
Stomach cells
5 days
Nerve cells in brain
As old as you are
Liver
1-1.5 years
Adult skeleton
7-10 years
Outer layer of skin
2 weeks

35. Changes in mitosis
Aging
Cancer
mutations

36. AGING Mitosis begins after fertilization and continues until death.
The rate of mitosis slows down with age.

37. Control of the Cell Cycle

39. Cyclins -Proteins that regulate the a cell’s progression through the cell cycle

40. CDKs (cyclin dependent kinases)- proteins that stop cells from progressing through the cell cycle
P53 – stops at G1 to; activates DNA repair if needed; triggers cell death if damage
If this is absent can cause cancer
P27- blocks entry into the S phase
Breast cancer diagnosis is determined by p27 levels

41. An abnormal cell should not be able to pass checkpoint

42. When Control is Lost: Cancer
Cancer results if cells do not respond to control mechanisms and start growing uncontrollably

43. CANCER – Cells mutate and grow, passing checkpoints
Normally a mutant cell is destroyed or self destructs.
Apoptosis
This does not occur in cancer cell

44. Cancer cell division
Unlike normal cells, cancer cells continue to divide indefinitely, even if they become densely packed.
Cancer cells will also continue dividing even if they are no longer attached to other cells.

46. Metastasis
A cancer tumor grows and spreads to other parts of body

47. Cancer animation

48. Causes of Cancer
carcinogen - Any substance that can induce or promote cancer.
2) Mutagens – A substances that cause mutations.

50. KINDS OF CANCER
Carcinomas- tumors grow in the skin and lining of organs. Ex. Lung and breast cancer
Sarcomas- tumors that grow in bone and muscle tissue.
Lymphomas- tumors that grow in the lymph and blood. Ex. Leukemia.

51. Cell Differentiation

52. Stem Cells- another way to produce new cells
Cellular Reproduction
Stem Cells- another way to produce new cells
Unspecialized cells that can develop into specialized cells when under the right conditions

53. Embryonic Stem Cells – unspecialized cells
Cellular Reproduction
Embryonic Stem Cells – unspecialized cells
After fertilization, the resulting mass of cells divides repeatedly until there are about –150 cells. These cells have not become specialized.

54. Cell differentiation
the process by which a less specialized cell becomes a more specialized cell type.

55. Cellular Reproduction
Adult Stem Cells
Found in various tissues in the body and might be used to maintain and repair the same kind of tissue

56. stem cells