1. Section Outline 10–1 Cell Growth Cell Division
A. Limits to Cell Growth
1. DNA “Overload”
2. Exchanging Materials
3. Ratio of Surface Area to Volume
4. Cell Division
Cell Division
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2. Limits to Cell Growth Why do cells need to divide?
Too much demand on its DNA (DNA overload)
As it grows it doesn’t make extra DNA (question #2)
Analogy (one library in Chicago)
Exchanging materials (food and oxygen in) (wastes out)
oxygen
waste
mito

3. 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
3. A cell’s volumes determines the rate at which food is used and wastes
produces
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4. Surface Area to Volume Ratio
SA/Vol =6:10 or 3:5 10 10 10
6. As the cell grows its volume increases
much more rapidly than its surface area, therefore…
7. a. The surface area to volume ratio decreases

5. Cell Division Cell Division
8. Cell division is the process by which a cell
divides into “daughter cells”
9. Reduces the volume and increases overall surface area

6. Section Outline 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
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7. Chromosomes Chromosomes – Made up of DNA (carries genetic material)
Must be copied before cells can divide
1. True – not visible prior to cell division
2. Before cell division chromosomes become visible. Consists of two identical sister chromatids (copied chromosomes)
chromosome
3. Sister chromatids

8. Figure 10–4 The Cell Cycle 4. Period of growth in between
Section 10-2
4. Period of growth in between
cell divisions
9. Cell do most of their growing
making proteins
G1 phase (grow)
M phase
10. Chromosomes copied (DNA)
S phase
(synthesis)
Division of cell
nucleus during M phase
G2 phase
11. Organelles required
for M phase produced
5. Cell cycle is series of events that cells go through as they grow and divide
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9. (Cell Division) Concept Map Cell Cycle Section 10-2 Go to Section:
includes
(Cell Division)
Mitosis
Interphase
Cytokinesis
is divided into
is divided into
G1 phase
S phase
Prophase
G2 phase
Metaphase
Telophase
Anaphase
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11. Onion Root Tip

12. Mitosis – Dividing of Cell Nucleus
Prophase
Metaphase
Anaphase
Telophase
Key terms:
13. Centrioles - structures that make spindle fibers
14. Spindle fibers – structure responsible for separating chromatids

13. Spindle fibers
Prophase (key events)
Chromosomes become visible
Nucleus begins to disappear
spindle fibers are formed from
centrioles
centrioles

14. Metaphase
19. The chromosomes line up across the center of the cell (moving along spindle fibers)

15. Anaphase
15. Chromosomes pulled apart (sister chromatids) until they form two groups near the “poles” of the spindle

16. Telophase
The nucleus begins to reform around each cluster of chromosomes
Cytokinesis – Division of cytoplasm.
Cell membrane or Cell plate is formed in between nuclei

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
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18. 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
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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
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20. 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
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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
Go to Section:

22. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming
Cell Division
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23. Understanding Chromosomes in Humans
Section 11-4
Chromosomes in Human Cells
How Many Chromosomes?
Normal human body cells each contain 46 chromosomes. The cell division process that body cells undergo is called mitosis and produces daughter cells that are virtually identical to the parent cell. 46 46
mitosis 46
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24. Understanding Chromosomes in Humans
Chromosomes in Human Cells
Where did we get our chromosomes?
From our parents
How many did you get from your father?
typically 23
How many did you get from your mother?
We often say that you got a set of chromosomes (23) from your mother and a set of chromosomes (23) from your father.

25. Homologous Chromosomes
Chromosomes in Human Cells
The set from your mother and the set from your father are called homologous chromosomes!
Why are they called homologous?
Because each set contains the same (homo) basic genetic information.

26. Homologous Chromosomes
Blue eye
gene
Brown eye
gene
From Mom
From Dad
Blonde
hair gene
Brown hair gene

27. Human cell with all its chromosomes
cytoplasm
nucleus

28. Introduction to Meiosis
Process by which sex cells (gametes) are formed
sperm cells or pollen cells (male cells)
egg cells (female cells)
Cell division of sex cells whereby, homologous chromosomes are separated

29. mitosis 46
Zygote (2n)
fertilization
Diploid 2n 46
Diploid 2n 46
Meiosis
Meiosis 23 23 23 23
Haploid 1n
Haploid 1n
sperm
eggs

30. Meiosis I

31. Crossing over during prophase I adds to genetic variaility
A = blonde hair a = brown hair
C = blue eyes c = brown eyes

32. Meiosis II

34. Polar Bodies

35. Genetic Variablity
Sexual Reproduction increases genetic variability by
Crossing over of sister chromatids during prophase I
Independent assortment during metaphase I
Random Fertilization