chapter 8. cells must divide for growth repair cells cannot just continue to grow larger for two...

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Page 1: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Chapter 8

Page 2: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Cells must divide forGrowthRepair

Page 3: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Cells cannot just continue to grow larger for two reasons:Exchanging materials

The surface area of the cell membrane must be large enough to support the volume of the cell.

Otherwise, the cell struggles keeping up with the exchange rate of food, oxygen and water across the membrane.

Information overloadToo many demands on the DNA to get its

information where it is needed.

Page 4: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Mitosis-The process by which a cell divides, forming

two “daughter” cellsThese daughter cells are identical to the

parent cell

Page 5: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Which cells ?Eukaryotic somatic (body) cells undergo

mitosisProkaryotic cells go through a process called

binary fission

Page 6: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

ChromosomesMade up of DNA wrapped tightly around

histone proteinsDNA + histones = chromatin fiber and looks

like “beads on a string”During mitosis chromatin condenses and

coils to form chromosomes

Page 7: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Chromosome:Sister chromatids- Each side of a duplicated

chromosomeCentromere- Center of a chromosome, holds

sister chromatids together

Page 8: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Chromosome number varies for each speciesHumans= 46 Cat= 38Fruit fly= 8

Page 9: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

The cell cycleMitosis is part of the cell’s life cycleThis cycle includes the following stages:

InterphaseMitosisCytokinesis

Page 10: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Interphase The longest phase of the cell cycleThe cell prepares to divide3 phases, or checkpoints, in Interphase

Page 11: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Phases of InterphaseG1 - intense cell growth, cells contents

duplicatedS - DNA is replicated (copied)G2 - more growth and final preparation for cell

divisionG0- cell enters this phase when something is

wrong and it either can’t or won’t divide. Ex: unstable environment, DNA was copied incorrectly, more cells not needed at that time

Page 12: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

The Cell Cycle

Page 13: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

After a cell goes through all the checkpoints, it is ready to divide!

The Mitotic phase of the cell cycle includes

ProphaseMetaphaseAnaphaseTelophase

Page 14: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

ProphaseNuclear envelope disappearsChromatin condensesChromosomes are first visibleCentrioles split and move to opposite sides of

the cell

Page 15: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Prophase

Page 16: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Prophase

Page 17: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

MetaphaseChromosomes line up in the middle of the

cell (equator)

Spindle fibers connect to chromosomes at the centromere

Metaphase = Middle

Page 18: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Metaphase

Page 19: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Metaphase (plant cell)

Page 20: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

AnaphaseSister chromatids pulled apart to opposite

sides Spindle fibers shortenAnaphase = Away, or Apart

Page 21: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Anaphase

Page 22: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Anaphase

Page 23: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

TelophaseTwo sets of genetic information on either side

of the cellNuclear envelope reforms around each setChromosomes no longer visible (unravel into

chromatin again)

Page 24: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Telophase

Page 25: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

After mitosis is complete, the cell has one thing left to do- split! (cytokinesis)

Page 26: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

CytokinesisSplitting of the cytoplasmForms two new distinct “daughter” cells Two cells are genetically identicalIn animals- Cell membrane “pinches off”In plants- Cell plate forms

Page 27: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

CytokinesisIn animals: Cell membrane “pinches off”

In plants: Cell plate forms

Page 28: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

Video linkshttp://www.youtube.com/watch?v=VlN7K1-

9QB0

http://www.youtube.com/watch?v=nPG6480RQo0&feature=related

Page 29: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the
Page 30: Chapter 8. Cells must divide for Growth Repair Cells cannot just continue to grow larger for two reasons: Exchanging materials The surface area of the

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