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Chapter 10 Cell Growth and Division
36

Chapter 10 Cell Growth and Division

Feb 24, 2016

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Chapter 10 Cell Growth and Division . Limits to Cell Growth. The larger a cell becomes, the more demands the cell places on its DNA and more trouble the cell has moving enough nutrients and wastes across the cell membrane. Growing Cells. 1 µ 2µ 3µ - PowerPoint PPT Presentation
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Page 1: Chapter 10  Cell Growth and Division

Chapter 10 Cell Growth

and Division

Page 2: Chapter 10  Cell Growth and Division

Limits to Cell Growth• The larger a cell becomes,

the more demands the cell places on its DNA and more trouble the cell has moving enough nutrients and wastes across the cell membrane

Page 3: Chapter 10  Cell Growth and Division

Growing Cells 1µ 2µ

4µ 6

5µ 6µ

Page 4: Chapter 10  Cell Growth and Division

How are surface area and volume affected by growth

Size / µm

1 2 3 4 5 6

Surface area / µm2

6 24 54 96 150 216

Volume / µm3

1 8 27 61 125 216

SA/V 6 3 2 1.5 1.2 1

Page 5: Chapter 10  Cell Growth and Division

DNA “Overload”• In Eukaryotic Cells, DNA is found in the

nucleus • As a cell increases in size, it does not

make extra copies of DNA• “Information Crisis” would occur if a

cell was to grow without limit• In time, the cell’s DNA would no longer

be able to serve the increasing needs of the growing cells

Page 6: Chapter 10  Cell Growth and Division

DNA “Overload”• There is another reason why the size of

cells are limited. • The rate of exchange depends on the

surface area of the cell. • The total area of its Cells Membrane• Rate at which food and oxygen are used

and waste products are produced depends on a cell’s volume

Page 7: Chapter 10  Cell Growth and Division

DNA “Overload”• Volume increases much more rapidly

then the surface area• It would be more difficult for a

larger cell to get oxygen and nutrients in and waste products out.

Page 8: Chapter 10  Cell Growth and Division

Cell Division Process by which a cell divides into two

daughter cells • Before it becomes too large, a growing

cell divides forming two “ Daughter” cells

• The cell replicates, or copies its DNA • Each daughter cell receives its own

genetic “library”

Page 9: Chapter 10  Cell Growth and Division
Page 10: Chapter 10  Cell Growth and Division

Chromosomes• Genetic information is passed on by

chromosomes• Chromosomes are made up of DNA and

Proteins• Cells of every organism have a specific

number of chromosomes• Chromosomes are not visible except

during cells division• Chromosomes condense at the

beginning of cell division

Page 11: Chapter 10  Cell Growth and Division
Page 12: Chapter 10  Cell Growth and Division

Chromosomes• Each chromosome s is replicated before

cell division because of this, each chromosome consists of two identical “Sister” chromatids

Page 13: Chapter 10  Cell Growth and Division

Chromatids• Attach at the centromere located

near the middle of the chromatids

Page 14: Chapter 10  Cell Growth and Division

Cell Cycle• A series of events that cells go

through as they grow and divide• During the cell cycle, a cell grows,

prepares for division, and divides to form tow daughter cells, each of which then begins the cycle again

Page 15: Chapter 10  Cell Growth and Division
Page 16: Chapter 10  Cell Growth and Division
Page 17: Chapter 10  Cell Growth and Division

Mitosis

I Prefer Mangos And Tangerines• Biologists divide the events of

mitosis into phases:• Interphase• Prophase• Metaphase• Anaphase• Telophase

Page 18: Chapter 10  Cell Growth and Division
Page 19: Chapter 10  Cell Growth and Division

Mitosis in ActionBlue shows DNA, Green shows

spindle fibers

Page 20: Chapter 10  Cell Growth and Division

Interphase• Has three phases: G1, S, & G2• G1 – Cells do most of their growing• S- Chromosomes are replicated and

the synthesis of DNA molecules take place

• G2 – shortest phase organelles and molecules required for cell divisions are produced

Page 21: Chapter 10  Cell Growth and Division
Page 22: Chapter 10  Cell Growth and Division

Prophase• The longest and first phase• Chromosomes becomes visible• Centrioles separated and take up

positions on opposite sides of the nucleus

• Centrioles help organize the spindle:– Fan like microtubule structure that

helps separate the chromosomes

Page 23: Chapter 10  Cell Growth and Division
Page 24: Chapter 10  Cell Growth and Division

Metaphase • The second phase• Chromosomes line up across the

center of the cell

Page 25: Chapter 10  Cell Growth and Division
Page 26: Chapter 10  Cell Growth and Division

Anaphase• The third phase• He centromeres separate allowing

the sister chromaids to separate

Page 27: Chapter 10  Cell Growth and Division
Page 28: Chapter 10  Cell Growth and Division

Telophase• The final phase• The chromosomes begin t disperse

into a tangle of dense material• A nuclear envelope reforms• Spindle begins to break apart• Nucleolus becomes visible • Mitosis is complete

Page 29: Chapter 10  Cell Growth and Division
Page 30: Chapter 10  Cell Growth and Division

Cytokinesis• Division of the cytoplasm itself• Occurs at the same time as

telophase

Page 31: Chapter 10  Cell Growth and Division
Page 32: Chapter 10  Cell Growth and Division

Cell Cycle Regulators • Cyclin

– Protein that regulates the cell cycle– Regulate the timing of the cell cycle in

Eukaryotic cells

Page 33: Chapter 10  Cell Growth and Division

Internal Regulators• Protein that respond to events inside

the cell are called Internal Regulators

Page 34: Chapter 10  Cell Growth and Division

External regulators• Proteins that respond to events

outside the cell are called external regulators

• Direct cells to speed up or slow down the cell cycle

Page 35: Chapter 10  Cell Growth and Division

Uncontrolled Cell Growth• Cancer

– A disorder in which some the body’s own cells lose the ability to control growth

– Cancers 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 for surrounding tissues.

Page 36: Chapter 10  Cell Growth and Division

Cancerous Tumor