1. Cellular Reproduction
Chapter 9
Cellular Reproduction

2. Why do cells need to reproduce?

3. Why are cells so small?

4. How is the surface area represented in a cell?
What is Surface Area?
How is the surface area represented in a cell?

5. What happens when the volume of a cell increases?
What is Volume?
What happens when the volume of a cell increases?

6. Mini-Lab 9.1 Investigate Cell Size
Cell Surface Area
(L x W x 6)
Cell Volume
(L x W x H)
Cell 1 m
Cell 2
0.001 m
Cell 3
2.5 cm (0.025 m)
Cell 4
30 cm (0.3 m)
Cell 5
15 m

7. Cell
Cell Size
Cell Surface Area
(L x W x 6)
Cell Volume
(L x W x H)
SA : V
Cell 1 m
300, 000 : 1
Cell 2
0.001 m
6000 : 1
Cell 3
2.5 cm (0.025 m)
240 : 1
Cell 4
30 cm
(0.30 m)
0.54
0.027
20 : 1
Cell 5
15 m
1350
3375
1 : 2.5

8. Cell
Cell Size
Cell Surface Area
(L x W x 6)
Cell Volume
(L x W x H)
SA : V
Cell 1
0.002 cm
Cell 2
0.1 cm
Cell 3
2.5 cm
Cell 4
30 cm
Cell 5
1500 cm

9. Cell
Cell Size
Cell Surface Area
(L x W x 6)
Cell Volume
(L x W x H)
SA : V
Cell 1
0.002 cm
3000:1
Cell 2
0.1 cm
0.06
0.001
60:1
Cell 3
2.5 cm
37.5
15.625
2.4:1
Cell 4
30 cm
5400
27000
0.2:1
Cell 5
1500 cm
13,500,000
3,375,000,000
0.004:1

10. Limits to Cell Size Smaller cells can better:
Exchange nutrients and expel wastes across the plasma membrane.
higher surface area to volume ratio (SA:V)
Transport substances within the cell.
diffusion
motor proteins along cytoskeleton
Communicate instructions for cellular functions.
signal proteins

11. Events of the Cell Cycle
During the cell cycle, the cell grows, replicates its DNA, and divides into two daughter cells. DNA synthesis takes place during the S phase. Cell division takes place during the M phase. G1 and G2 are gap phases.

12. The Cell Cycle The entire process of growing and dividing
Repeated continuously
Creates two cells from one cell
Normal animal cells – takes hours
3 main stages:
Interphase
Mitosis
Cytokinesis

13. Stages of Cell Cycle Interphase Includes G1, S, G2
Followed by Cell Division
Includes Mitosis and Cytokinesis

14. Interphase Period of time during which the cell, 3 parts (substages)
grows and develops,
carries out cellular functions,
and makes copies of its DNA in preparation for cell division
3 parts (substages)
G1 – Gap 1
S – Synthesis
G2 – Gap 2

15. Stages of Interphase Gap 1 (G1) Immediately after cell divides
Cell is growing and carrying out normal functions
Cell is preparing to replicate DNA
Synthesis Phase (S)
Cell copies its DNA in preparation for cell division
Gap 2 (G2)
Cell prepares for division of its nucleus
Makes proteins needed for cell division

16. Cell Division
When a cell reaches its maximum size, the nucleus initiates cell division.
Cell division – the splitting of a single cell into two cells.
‘Big Bang’ by M. Ormestad ©2006 All rights reserved

17. Cell Division Cells divide so that an organism… can grow.
increases mass of organism
changes organism - differentiation
can repair damaged cells and tissues.
regeneration
maintenance
can reproduce.

18. Mitosis (Cell Division)
Stage of cell cycle where the nucleus divides
Includes four stages:
Prophase
Metaphase
Anaphase
Telophase

19. Cytokinesis (Cell Division)
Process where the cell’s cytoplasm divides and creates a new cell

20. Chapter 9.2
Mitosis and Cytokinesis

21. Mitosis & Cytokinesis Mitosis Cytokinesis
the cell’s nuclear material divides
4 parts (substages)
Cytokinesis
the cell cytoplasm is divided into two daughter cells

22. Genetic Material in the Cell
Question 1: In what stage of the cell cycle is the DNA copied?
Answer 1: Synthesis
Question 2: Why is this important?
Answer 2: It prepares the cell for cell division
Question 3: How is DNA organized in a cell?
Hint:
Answer:
Chromosomes

23. Chromosomes
Structures that contain the genetic material of an organism
Only visible during mitosis
Formed when chromatin is wound tightly around proteins

25. The DNA strands wraps around proteins called histones
The continue to wrap around forming nucleosomes

26. For most of the cell’s life, the DNA is contained in the chromatin state
In cell division, chromatin organizes into distinct chromosomes structures
Chromosome Formation

27. Chromosome Structure

28. Centromere Sister chromatids
Structure where the sister chromatids are attached
Sister chromatids
Identical copies
Copies created during synthesis of interphase
Attached at beginning of mitosis

29. Stages of Mitosis Prophase Metaphase Anaphase Telophase
Human cell undergoing cytokinesis from M. Pines, Inside the Cell: The New Frontier of Medical Science. U.S. Dept. of Health, Education, and Welfare, 1978.

30. Prophase 1st stage longest Chromatin condenses into chromsomes
Nuclear membrane disintegrates
Nucleolus disappears
Chromosomes attach to spindle apparatus

31. End of Prophase Spindle apparatus forms Spindle fibers Centrioles
Chromosomes attach to spindle fibers

32. Metaphase
2nd stage
shortest
sister chromatids pulled along the spindle apparatus toward the center of the cell
line up along the middle, or equator

33. Anaphase 3rd stage sister chromatids are pulled apart spindle shorten
separates chromatids into two identical sets

34. Telophase 4th & last stage
“opposite of prophase”
Chromosomes arrive at poles of spindle apparatus
decondense
Nuclear membrane and nucleolus reform
Spindle apparatus is broken down or recycled
May occur simultaneously with cytokinesis

35. Another Look at Mitosis

36. Cytokinesis Division of the cytoplasm into two daughter cells
Animal cells
microfilaments constrict
cell membrane pinches cell in two
Plant cells
construct a cell plate
new cell wall forms on either side of cell plate
Prokaryotic cells
DNA copies attach to plasma membrane
plasma membrane grows and pulls DNA copies apart
cell membrane pinches into two cells

37. Mitosis in Motion http://www.johnkyrk.com/mitosis.html
mitosis.html

38. Chapter 9.3
Cell Cycle Regulation

39. Normal Cell Cycle In eukaryotic cells, cell division driven by
A protein cyclin binding to an enzyme cyclin-dependent kinase (CDK)

40. Normal Cell Cycle
Different cyclin/CDK combinations control different activities in the cell cycle:
Signals the start of the cell cycle during G1
Signals DNA replication
Signals protein synthesis
Signals nuclear division
Signals the end of the cell cycle

41. Normal Cell Cycle
The cell cycle also has checkpoints to monitor the cycle and stop it if something goes wrong

42. Abnormal Cell Cycle: Cancer
Cancer is uncontrolled cell growth that occurs when there is a failure in the regulation of the cell cycle
Cancer cells crowd out other normal cells and can intrude other organs; may lead to death of the organism from loss of tissue

43. Abnormal Cell Cycle: Cancer
Cancer cells occur when mutations takes place in segments of DNA
Mutation cause changes in the productions of proteins, including cyclins
Substances that cause cancer are carcinogens

44. Apoptosis Normal, Programmed cell death
Occurs in cells that are damaged beyond repair
Can help protect cells from cancer

45. Stem Cells Cells are designed for specialized functions
Stem cells are unspecialized cells that can develop into specialized cells
Two types of stem cells:
Embryonic
Adult

46. Stem Cells The Nature of Stem Cells Go, Go Stem Cells
Go, Go Stem Cells