1. Section 10-1
Getting Through
Materials move through cells by diffusion. Oxygen and food move into cells, while waste products move out of cells. How does the size of a cell affect how efficiently materials get to all parts of a cell?
Work with a partner to complete this activity.
1. On a sheet of paper, make a drawing of a cell that has the following dimensions: 5 cm x 5 cm x 5 cm. Your partner should draw another cell about one half the size of your cell on a separate sheet of paper.
2. Compare your drawings. How much longer do you think it would take to get from the cell membrane to the center of the big cell than from the cell membrane to the center of the smaller cell?
3. What is the advantage of cells being small?

2. 3. Ratio of Surface Area to Volume 4. Cell Division
Section Outline
Section 10-1
10–1 Cell Growth
A. Limits to Cell Growth
1. DNA “Overload”
2. Exchanging Materials
3. Ratio of Surface Area to Volume
4. Cell Division

3. There are 2 main reasons why cells divide rather than growing larger:
Section 10-1
There are 2 main reasons why cells divide rather than growing larger:
DNA “Overload”-when a cell is small, the information stored in that DNA meets the needs of the cell; as a cell grows it usually does not make extra copies of DNA which created an information shortage.
ex. Small town library

4. Ratio of Surface Area to Volume-
Section 10-1
Material Exchange-all food, water, oxygen and wastes must pass through the cell membrane. The rate at which this exchange takes place depends on the surface area of the cell.
Ratio of Surface Area to Volume-
Volume increases much more rapidly than the surface area, causing the ratio of surface area to volume to decrease.
ex. Main street

5. Ratio of Surface Area to Volume in Cells
Section 10-1
Cell Size
Surface Area (length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area to Volume

6. The process by which a cell divides into 2 new daughter cells.
Section 10-1
Division of the Cell
The process by which a cell divides into 2 new daughter cells.
Before the cell divides, DNA replication takes place.
These processes allow the cells to:
a. Reduce volume
b. Increase surface area to volume ratio
c. Maintain available genetic information

7. Section 10-2
Cell Cycle
The cell cycle represents recurring events that take place in the period of time from the beginning of one cell division to the beginning of the next. In addition to cell division, the cell cycle includes periods when the cell is growing and actively producing materials it needs for the next division.
1. Why is the cell cycle called a cycle?
2. Why do you think that it is important for a cell to grow in size during its cell cycle?
3. What might happen to a cell if all events leading up to cell division took place as they should, but the cell did not divide?

8. C. Events of the Cell Cycle D. Mitosis 1. Prophase 2. Metaphase
Section Outline
Section 10-2
10–2 Cell Division
A. Chromosomes
B. The Cell Cycle
C. Events of the Cell Cycle
D. Mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
E. Cytokinesis

9. Video 1

10. Section 10-2
Chromosomes-are comprised of DNA and protein. These carry the genetic information in eukaryotic cells. Only visible during cell division.
Before cell division, each chromosome is replicated, creating identical “sister” chromatids. During cell division each chromatid will go to the 2 new cells.

11. 3. Divides to form 2 daughter cells
Section 10-2
Cell Cycle-
1. Cell grows
2. Prepares for division
3. Divides to form 2 daughter cells
4. Daughter cells begin cycle again

12. Figure 10–4 The Cell Cycle Section 10-2 G1 phase M phase S phase

13. This phase consists of: G1 phase-main growth of a cell
Section 10-2
Interphase
This phase consists of:
G1 phase-main growth of a cell
S phase- DNA replicated
G2 phase-many organelles and molecules required for cell
division are produced

14. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

15. Mitosis part of eukaryotic cell division in which the nucleus divides
Section 10-2
Mitosis
part of eukaryotic cell division in which the nucleus divides
Lasts a few minutes to several days.
Four phases:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

16. This is the first and longest phase. Events that take place include:
Section 10-2
Prophase
This is the first and longest phase.
Events that take place include:
1. chromosomes become visible
2. centrioles separate and move to opposite sides
3. spindle (fan-like microtubule structure) forms
4. chromosomes attach to spindle fibers

17. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

18. Second phase of mitosis Events that take place include:
Section 10-2
Metaphase
Second phase of mitosis
Events that take place include:
1. chromosomes line up in the center of the cell
2. microtubules connect the centromere of each chromosome to the two poles of the spindle

19. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

20. Events that take place include:
Section 10-2
Anaphase
Third phase of mitosis
Events that take place include:
1. the centromeres that join the sister chromatids split allowing the sister chromatids to become individual chromosomes
2. chromosomes move towards the ends of the cell

21. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

22. Fourth and final phase of mitosis Events that take place include:
Section 10-2
Telophase
Fourth and final phase of mitosis
Events that take place include:
1. chromosomes are at opposite ends of cell and lose shape
2. two new nuclear envelopes will form around the chromosomes

23. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

24. Section 10-2
Cytokinesis
Animal cells-cell membrane is drawn inward until the cytoplasm is pinched into 2 equal parts
Plant cells-a cell plate forms midway between the divided nuclei. This eventually becomes a cell membrane and a cell wall.

25. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

26. Concept Map Cell Cycle Section 10-2 includes M phase (Mitosis)
Interphase
is divided into
is divided into
G1 phase
S phase
Prophase
G2 phase
Metaphase
Telophase
Anaphase

27. Interest Grabber
Section 10-3
Knowing When to Stop
Suppose you had a paper cut on your finger. Although the cut may have bled and stung a little, after a few days, it will have disappeared, and your finger would be as good as new.
1. How do you think the body repairs an injury, such as a cut on a finger?
2. How long do you think this repair process continues?
3. What do you think causes the cells to stop the repair process?

28. 10–3 Regulating the Cell Cycle A. Controls on Cell Division
Section Outline
Section 10-3
10–3 Regulating the Cell Cycle
A. Controls on Cell Division
B. Cell Cycle Regulators
1. Internal Regulators
2. External Regulators
C. Uncontrolled Cell Growth

29. Control of Cell Division
Section 10-3

30. Figure 10–8 Effect of Cyclins
Section 10-3
The sample is injected into a second cell in G2 of interphase.
A sample of cytoplasm is removed from a cell in mitosis.
As a result, the second cell enters mitosis.

31. Click the image to play the video segment.
Animal Cell Cytokinesis
Click the image to play the video segment.
Video 2

32. Interest Grabber Answers
1. On a sheet of paper, make a drawing of a cell that has the following dimensions: 5 cm x 5 cm x 5 cm. Your partner should draw another cell about one half the size of your cell on a separate sheet of paper.
2. Compare your drawings. How much longer do you think it would take to get from the cell membrane to the center of the big cell than from the cell membrane to the center of the smaller cell?
It would take twice the amount of time.
3. What is the advantage of cells being small?
If cells are small, materials can be distributed to all parts of the cell quickly.
Section 1 Answers

33. Interest Grabber Answers
1. Why is the cell cycle called a cycle?
It represents recurring events.
2. Why do you think that it is important for a cell to grow in size during its cell cycle?
If a cell did not grow in size, each cell division would produce progressively smaller cells.
3. What might happen to a cell if all events leading up to cell division took place as they should, but the cell did not divide?
Students may infer that a cell that undergoes all sequences of the cell cycle would grow increasingly larger—to a point at which the cell could no longer exchange materials with the environment efficiently enough to live.
Section 2 Answers

34. Interest Grabber Answers
1. How do you think the body repairs an injury, such as a cut on a finger?
The cut is repaired by the production of new cells through cell division.
2. How long do you think this repair process continues?
Cell division continues until the cut is repaired.
3. What do you think causes the cells to stop the repair process?
Students will likely say that when the cut is filled in, there is no room for more cells to grow.
Section 3 Answers

35. This slide is intentionally blank.
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