1. Cell Growth and Division
Chapter 10

2. By the time you finish reading this sentence, 50 million of your cells will have died and been replaced by others. Some are lost through 'wear and tear’, some just reach the end of their life, and others deliberately self-destruct.

3. A. Importance of Cell Growth and Division
Allows for an organism’s growth
Replaces damaged cells
Allows cells to maintain the proper surface area-to-volume ratio

4. WHY CAN’T A CELL JUST KEEP GETTING BIGGER?
HOWEVER>>>>The larger a cell becomes, the more demands it places on it’s DNA. It also has more trouble moving nutrients and wastes across the cell membrane.

5. Allows cells to maintain the proper surface area-to-volume ratio
1. Cells cannot simply grow by increasing in size.
Cells of adults and children of a species are the same size.

6. The Cell membrane determines the surface area of the cell.
The volume of a cell is determined by the amount of cytoplasm present with all its contents.
As a cell’s size increases, its volume increases much faster than its surface area.
      
The cell overcomes these problems through the process of cell division.

7. Ratio of Surface Area to Volume   
As the size of a cell increases, its volume increases faster than the surface area.
The decrease in the cell’s ratio of surface area to volume makes it more difficult for the cell to move needed materials in and waste products out quickly enough for the cell to survive.

8. Find surface area

9. Find surface area

10. Find surface area

11. Find surface area

12. Find Volume

13. Find Volume

14. Find Volume

15. Find Volume

16. Find Ratio

17. Find Ratio

18. Find Ratio

19. Find Ratio

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

21. Why do animals shed their skin?

22. Cell Division! More next time!
Quiz over Ch 10.1 Cell Growth
Next Time

23. Regulating Cell Division (Cell Cycle)
Cells stop growing when they come in contact with each other-such as when a wound is healing

24. a. Internal Cyclins-usually controls cell division events inside the cell like the beginning and end of cell cycle stages.
Cyclins-proteins within the cell that regulate the timing of eukaryotic cell division
b. External Cyclins -for events outside the cell. These usually speed up or slow down the cell cycle and heal wounds.

25. CANCER
Occurs when cells do not respond to normal signals that regulate growth
*Most cancer cells have defect in the p53 gene

26. Malignant Tumor-invasive uncontrolled growth of cells Skin Cancer
Benign Tumor-a tumor that only grows in one place. Noninvasive and usually treatable

27. Cell Division! Ch 10.2

28. Cell Reproduction
Prokaryotes Bacteria
Eukaryotes Plants & animals

29. Prokaryotes Lack a nucleus Have a single chromosome
Reproduce asexually by binary fission
Include bacteria

30. Steps in Binary Fission
Cells increase their cell mass slightly
DNA & cell components are replicated
Each cell divides into 2 daughter cells

31. Binary Fission of Bacterial Cell

32. E. Coli Dividing by Binary Fission

33. Eukaryotes Contain a nucleus & membrane bound organelles
Asexually reproduce cells by mitosis

34. Vocabulary Mitosis = division of the cell nucleus and its contents
Cytokinesis = the division of cell cytoplasm into two identical daughter cells
Chromatin = the combination of DNA and histone proteins
Chromosome-main organelle involved in Cell Cycle
Diploid = Two copies of each chromosome, one paternal, one maternal

35. Chromosomes in the Larger Scheme

36. Chromosome Structure
1 – Chromatid-because each has an identical half they are “sister” chromatids
2 – Centromere
3 – Short arm
4 – Long arm

37. Chromosomes Made from DNA Formed from chromatin Genetic material
directs activities
determines characteristics
Formed from chromatin
Uncoiled DNA
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38. From: http://www.rothamsted.bbsrc.ac.uk/
Chromosomes (cont.)
Each chromosome (at this point) is made up of 2 identical chromatids
Joined strands of identical duplicated genetic material
Joined at centromere
Chromatids separate and each cell has identical information
Formed in S phase of cell cycle
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From:
notebook/courses/guide/chromo.htm

39. From: http://www.accessexcellence.org/RC/VL/GG/nucleosome.html
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40. 4/16/2017

41. Sets of chromosomes Each human somatic (body) cell
23 pairs of chromosomes (46 total)
Homologous chromosomes
Each pair is called homologous
Similar in size, shape and genetic content
Not identical!
One from each parent
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42. 4/16/2017

43. Cell Cycle Interphase Mitosis - Division of the nucleus
G1 - growth and normal cell activity
G0 – never divides again
S - Synthesis of DNA
DNA replication
G2 - Growth for division, organelles double
Mitosis - Division of the nucleus
Cytokinesis - Division of the cytoplasm (cell)
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44. Cell Cycle Stages in growth & division G1 Phase S Phase G2 Phase
M Phase
Cytokinesis

45. Growth for division Organelles double Growth & normal cell activity G0
DNA replication
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46. Length of cell cycle Ranges from 20 minutes to 20 hours
Some cells divide constantly and others never divide
Muscle cells
Red Blood cells
Skin cells
Bone cells
Nerve cells
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47. G1 Phase First growth stage Cell increases in size
Cell prepares to copy its DNA

48. Synthesis (S) Phase Copying of all of DNA’s instructions
Chromosomes duplicated

49. G2 Phase Time between DNA synthesis & mitosis Cell continues growing
Needed proteins produced

50. Mitosis A process in which eukaryotic cells form two identical nuclei.
Significance of the
process of mitosis
Mitosis
A process in which eukaryotic cells form two identical nuclei.
Each cell receives a complete set of chromosomes
division of the nucleus
Cytokinesis
division of the cytoplasm
2 independent cells (genetically identical)
Different in plant and animals
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51. M Phase Cell growth & protein production stop
Cell’s energy used to make 2 daughter cells
Called mitosis or karyokinesis (nuclear division)

52. Life Cycle of a Cell
Mitosis is a cycle with no beginning or end.

53. Interphase – Resting Stage
Cells carrying on normal activities
Chromosomes aren’t visible
Cell metabolism is occurring
Occurs before mitosis

54. Interphase

55. D. Stages of Mitosis
Prophase
Metaphase
Anaphase
Telophase

56. Major Events in Mitosis

57. Cells Undergoing Mitosis

58. Steps in Prophase DNA coils tightly & becomes visible as chromosomes
Nuclear membrane disappears
Nuceolus disappears
Centrioles migrate to poles
Spindle fibers begin to form and the chromosomes attach

59. Eukaryotic Chromosome
Spindles attach here

60. Prophase Plant Cell Animal Cell Spindle fibers Centrioles
Photographs from:

61. Steps in Metaphase
Spindle fibers from centrioles attach to each chromosome
Cell preparing to separate its chromosomes
Cell aligns its chromosomes in the middle of the cell

62. Metaphase

63. Metaphase Plant Cell Animal Cell
Photographs from:

64. Steps in Anaphase Cell chromosomes are separated
Spindle fibers shorten so chromosomes pulled to ends of cell

65. Mitotic Spindle

66. Anaphase

67. Anaphase Plant Cell Animal Cell
Photographs from:

68. Steps in Telophase Separation of chromosomes completed
Cell Plate forms (plants)
Cleavage furrow forms(animals)
Nucleus & nucleolus reform
Chromosomes uncoil

69. Telophase
       Plant            
Animal

70. Telophase Plant Cell Animal Cell
Photographs from:

71. Cytokinesis Occurs after chromosomes separate
Forms two, identical daughter cells

72. Cytokinesis
Cell Plate Forming in Plant Cells

73. Animal Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

74. Plant Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

75. 4/16/2017
From:

76. 4/16/2017

77. 4/16/2017
Mitosis/Photographs/whitefish_mitosis_prophase_metaphase_anaphaseX400.jpg

78. 4/16/2017 http://faculty.clintoncc.suny.edu/faculty/michael.gregory/
files/Bio%20101/Bio%20101%20Laboratory/Mitosis
/Photographs/whitefish_mitosis_telophaseX400.jpg
files/Bio%20101/Bio%20101%20Laboratory/
Mitosis/Photographs/whitefish_mitosis_anaphaseX400.jpg
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79. Quiz Next time!

80. Regulating Cell Division (Cell Cycle)
Cells stop growing when they come in contact with each other-such as when a wound is healing

81. a. Internal Cyclins-usually controls cell division events inside the cell like the beginning and end of cell cycle stages.
Cyclins-proteins within the cell that regulate the timing of eukaryotic cell division
b. External Cyclins -for events outside the cell. These usually speed up or slow down the cell cycle and heal wounds.

82. Malignant Tumor-invasive uncontrolled growth of cells Skin Cancer
Benign Tumor-a tumor that only grows in one place. Noninvasive and usually treatable

83. CANCER
Occurs when cells do not respond to normal signals that regulate growth
*Most cancer cells have defect in the p53 gene

84. Make a little book Page one – Title
Page two – interphase including G1, S, G2
Page three – prophase
Page four – metaphase
Page five – anaphase
Page six – telephase
Page seven – cytokinesis
Page eight – the end

85. Test information Cell Cycle Mitosis completed Chromosomes Mitosis
Order
S phase
Cancer
Interphase
Mitosis completed
What does each cell have?
Chromosomes
Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
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