End Show Slide 1 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle.
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End Show Slide 1 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle
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Transcript of End Show Slide 1 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle.
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Slide 1 of 18
Copyright Pearson Prentice Hall
10-3 Regulating the Cell Cycle
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Slide 2 of 18
10-3 Regulating the Cell Cycle
Copyright Pearson Prentice Hall
Controls on Cell Division
Contact Inhibition
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10-3 Regulating the Cell Cycle
Slide 3 of 18
Copyright Pearson Prentice Hall
Controls on Cell Division
Controls on Cell Division
• Contact inhibition – Cells stop growing when in contact with other cells
• Cell growth can be turned on and off by internal and external regulators.
• Once cells reach adult stage they grow and divide at different rates depending on cell type.
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Slide 4 of 18
10-3 Regulating the Cell Cycle
Copyright Pearson Prentice Hall
Cell Cycle Regulators
Cell Cycle Regulators
• Cell cycle is regulated by a specific protein called cyclin.
• amount of protein rises and falls in time with the cell cycle
• Cyclin directs the cell to go into mitosis.
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Slide 5 of 18
10-3 Regulating the Cell Cycle
Copyright Pearson Prentice Hall
A sample of cytoplasmis removed from a cellin mitosis.
The sample is injectedinto a second cell inG2 of interphase.
As result, the secondcell enters mitosis.
Cyclins were discovered during a similar experiment to this one.
Cell Cycle Regulators
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Slide 6 of 18
10-3 Regulating the Cell Cycle
Copyright Pearson Prentice Hall
Internal Regulators
Internal regulators - Proteins that respond to events inside the cell
Internal regulators allow the cell cycle to proceed only when certain processes have happened inside the cell.
Cell Cycle Regulators
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Slide 7 of 18
10-3 Regulating the Cell Cycle
Copyright Pearson Prentice Hall
Cell Cycle Regulators
External Regulators
External Regulators - proteins that respond to events outside the cell.
External regulators direct cells to speed up or slow down the cell cycle.
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Slide 8 of 18
10-3 Regulating the Cell Cycle
What is the Life span of a human cell?
It depends on what cell it is. e.g. blood cell, skin cell, stomach tissue cell
Recent studies have shown that few cells live as long as the individual they belong to without renewal. A majority, if not all, the cells making up the cerebral cortex belong to this small group. The life span of some other human cells are as follows:
Copyright Pearson Prentice Hall
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Slide 9 of 18
10-3 Regulating the Cell Cycle Lifespan of select human cells:
• Cell Type – Lifespan
• Granulocytes -- 10 hours to 3 days
• Stomach lining cells -- 2 days
• Sperm cells -- 2-3 days
• Stomach lining cells -- 2 days
• Colon cells -- 3-4 days
• Epithelia of small intestine -- 1 week or less
Copyright Pearson Prentice Hall
•Platelets -- 10 days
•Skin epidermal cells -- 2 - 4 weeks
•Lymphocytes -- 2 months - a year
•Red blood cells -- 4 months
•Stomach lining cells -- 2 days
•Macrophages -- months - years
•Endothelial cells -- months - years
•Pancreas cells -- 1 year or more
•Bone Cells -- 25 - 30 years
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10-3 Regulating the Cell Cycle
Slide 10 of 18
Copyright Pearson Prentice Hall
Uncontrolled Cell Growth
Uncontrolled Cell Growth xxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Cancer is a disorder in which some of the body's own cells lose the ability to control growth.
Cancer cells
•divide uncontrollably
• form masses of cells called tumors
•Tumors can damage surrounding tissues
•Metastatic cancer cell – cell that breaks loose from tumor and spreads throughout the body
•Cancer is usually caused by a defect in gene p53
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Slide 11 of 18
Copyright Pearson Prentice Hall
10-3
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Slide 12 of 18
Copyright Pearson Prentice Hall
10-3
The cell cycle is believed to be controlled by proteins called
a. spindles.
b. cyclins.
c. regulators.
d. centrosomes.
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Slide 13 of 18
Copyright Pearson Prentice Hall
10-3
Proteins that respond to events inside the cell are called
a. internal regulators.
b. external regulators.
c. cyclins.
d. growth factors.
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Slide 14 of 18
Copyright Pearson Prentice Hall
10-3
Once a multicellular organism reaches adult size, the cells in its body
a. stop dividing.
b. grow and divide at different rates, depending on the type.
c. have the same life span between cell divisions.
d. undergo cell division randomly.
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Slide 15 of 18
Copyright Pearson Prentice Hall
10-3
One effect of an internal regulator is that a cell will not begin mitosis until
a. it becomes too large.
b. the cell’s growth is stimulated.
c. it is in physical contact with other cells.
d. all its chromosomes have been replicated.
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Slide 16 of 18
Copyright Pearson Prentice Hall
10-3
One factor common to almost all cancer cells is
a. a lack of cyclin.
b. a defect in gene p53.
c. exposure to tobacco smoke.
d. exposure to radiation.
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