1. Chapter 10 Cell Growth & Division
Section 10–1 Cell Growth

2. Objectives
What problems does growth cause for cells?

3. Limits To Cell Growth Key Concept:
The Larger A Cell Becomes, The More Demands The Cell Places On Its DNA And The More Trouble The Cell Has Moving Enough Nutrients And Waste Across The Cell Membrane

4. DNA Overload Extra Copies Of DNA Are Not Made
Like A Small Town – Infrastructure Needs To Grow As The Town Grows

5. DNA Overload

6. Exchanging Materials Cell Membrane (Surface Area) Nutrients Enter
Waste And Products Leave
The Amounts Of Nutrients Needed And The Amount Of Waste Produced
Depends On The Cells Volume

7. Ratio of Surface Area To Volume
As Cell Size Increases
Volume Increases More Rapidly Than Surface Area (cell membrane)
Cell Membrane Can Not Cycle Nutrients and Wastes Fast Enough.

8. To Large Before They Become Cell Division Cells Divide
Cell Division Is The Process By Which A Cell Divides Into Two Daughter Cells

9. Before A Cell Divides It Replicates Its DNA So Each Cell Has
Cell Division
Before A Cell Divides
It Replicates Its DNA
So Each Cell Has
An Exact Copy

10. Chapter 10 Cell Growth & Division
10-2 Cell Division

11. Objectives What are the main events of the cell cycle?
What are the four phases of mitosis?

12. Chromosomes DNA + Protein
Carry Genetic Information From One Generation of Cell to the Next Generation of Cells
Made Up Of:
DNA + Protein

13. Chromosomes Every Organism Has A Specific Number Of Chromosomes
Fruit Flys = 8
Carrots = 18
Humans = 46
Giraffe = 30
King Crab = 208

14. Chromosomes Not Visible Except During Division
Well Before Division They Duplicate

15. Chromosomes Chromatids Centromere
Just Before Division Chromosomes Condense Into Compact, Visible Structures Called Chromatids
Centromere
Each Chromosome Has Two, Identical Chromatids Connected By A Centromere

16. Chromosomes Chromatid A Copy of Chromatid A Centromere Kenitophore
Microtubules or
Spindle Fibers
Copy of Chromatid A
Chromatid A

19. The Cell Cycle Key Concept: During The Cell Cycle: A Cell Grows
Prepares For Division
Divides To Form Two Daughter Cells
Each Daughter Cell Then Begins The Cycle Again

20. Cell Cycle

21. Time In-Between Cell Divisions
Interphase
Time In-Between Cell Divisions

22. Cell Division or M phase

24. Events Of The Cell Cycle
Interphase
May Be Quite Long
Divided Into 3 Parts

25. The 3 Parts of Interphase
G1 Phase
Cell Grows In Size
Synthesize New Proteins & Organelles

26. The 3 Parts of Interphase
S Phase
Chromosomes Are Replicated
Once This Phase Begins The Cell Completes Division

27. The 3 Parts of Interphase
G2 Phase
Organelles & Proteins Required For Mitosis Are Produced
Cell Is Now Ready To Enter
M Phase (Mitosis)

28. Mitosis
Key Concept:
Biologists Divide The Events Of Mitosis Into Four Phases:
Prophase
Metaphase
Anaphase
Telophase

29. Prophase 1st & Longest Phase Chromosomes Become Visible
Centrioles Separate & Take Up Position On Opposite Sides Of The Nucleus
Spindle Begins To Form

30. Prophase In Animals In Plants
Spindle Fibers Attach To Centromere On Each Chromatid
In Plants
No Centromere, Spindle Fibers Still Form From Centrosomes

31. Late Prophase
Nucleolus Disappears
Nuclear Envelope Breaks Down

33. Metaphase Short Just A Few Minutes
Chromosomes Line Up Across Center Of The Cell
Microtubules Connect The Centromere To The Poles Of The Spindle

35. Anaphase Centromeres Separate Sister Chromatids Separate
Each Set Of Chromosomes Pulled To Their Poles

37. Telophase Chromosomes Disperse New Nuclear Envelopes Form
Spindle Breaks Apart
Nucleolus Reforms

39. Cytokinesis There Are Now Two Nuclei In One Cell
Cytokinesis Is The Division Of The Cytoplasm Into Two Cells
The Cell Membrane Is Drawn Inward Until The Cell Pinches Into Two Equal Parts

40. Cytokinesis In Plants
A New Cell Plate Forms In The Middle Of The Cell Which Attaches To, And Becomes Part Of, The Cell Wall

42. Chapter 10 Cell Growth & Division
Section 10-3
Regulating Cell Growth

43. Objectives How is the cell cycle regulated?
How are cancer cells different from other cells?

44. Controls On Cell Division
When Cells In Cell Cultures Come In Contact With Each Other, They Stop Growing.
Why?

45. Controls On Cell Division
If A Hole Is Made In The Cell Culture, Cell Growth Will Restart & Continue Until The Hole Is Filled.
Why?

46. Controls On Cell Division
In Your Body The Rate Of Cell Growth Is Controlled.
Injury Causes Rapid Division Until The Wound Is Healed. Then Division Slows Again.
Why?

47. Cell Cycle Regulators Key Concept:
Cyclins Regulate The Timing Of The Cell Cycle In Eukaryote Cells.
Discovered In The 1980’s
Cyclins Are A Family Of Closely Related Proteins That Rise & Fall Within The Cell With The Cell Cycle

48. Cyclins & Cell Cycle

49. Cell Cycle Regulators Cyclins
When Injected Into Non-Dividing Cells, Cyclins Cause Mitotic Spindles To Form.

50. Cell Cycle Regulators Cyclins
When Injected Into Non-Dividing Cells, Cyclins Cause Mitotic Spindles To Form.

51. Cell Cycle Regulators Cyclins
When Injected Into Non-Dividing Cells, Cyclins Cause Mitotic Spindles To Form.

52. Other Regulator Proteins Continue To Be Found.
Cell Cycle Regulators
Other Regulator Proteins Continue To Be Found.

53. Other Internal Regulators
These Proteins Respond To Events Inside The Cell.
Several Make Sure The Cell Does Not Enter Mitosis Until All Chromosomes Have Been Replicated.
Others Stop The Cell From Entering Anaphase Until All Chromosomes Are Attached To The Mitotic Spindle

54. Cyclins & Cell Cycle

55. External Regulators These Respond To Events Outside The Cell
They Direct The Cell To Speed Up Or Slow Down The Cell Cycle
These Include Growth Factors

56. Growth Factors
Very Active During
Embryonic Development
Wound Healing

57. Other External Regulators
Molecules On The Cell Membrane Of Neighboring Cells Slow The Growth Process
They are like sensors that signal the cell to slow/stop growth

58. Uncontrolled Cell Growth

59. Uncontrolled Cell Growth
Key Concept:
Cancer Cells Do Not Respond To The Signals That Regulate The Growth Of Most Cells. As A Result, They Form Masses Of Cells Called Tumors That Can Damage Surrounding Tissue.

60. Uncontrolled Cell Growth
Metastasis
Cancer Cells Break Loose From The Tumor And Invade Tissues Throughout The Body

61. Some Carcinogen Sources
Smoking
Radiation
Viral Infection

62. p53 Gene
Usually Stops The Cell Cycle Until Chromosomes Have Been Properly Replicated.
High Percentage Of Cancers Cells Have Defects At This Gene Site