Transcript 10.3_Regulating_the_Cell_Cycle

1 Review Name the two types of proteins that regulate
the cell cycle and how do they work
Form a Hypothesis Write a hypothesis about what
you think would happen if cyclins were injected into
a cell during mitosis. How would you test your
hypothesis
2 Compare and Contrast How are the growth of a
tumor and the repair of a scrape on your knee similar
and how are they different
3 Infer Why do you think it is important that cells have
a “control system” to regulate the timing of cell
division
CH 10 CELL GROWTH AND DEVELOPMENT
10.3 Regulating the Cell Cycle
Controls on Cell Division
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Controlled by regulatory proteins both inside and
outside the cell
Can be turned on and off
Cells are stimulated to divide rapidly with a broken
bone and slow when healing nears completion.
Cyclins

Proteins that regulate the timing of the cell cycle.
Regulatory Proteins

Internal regulators
 Respond
to events inside a cell
 Allow the cell cycle to proceed only once certain
processes have occurred
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External regulators
 Respond
to events outside the cell
 Direct cells to speed up or slow down the cell cycle.
Regulatory Proteins

Growth factors
 External
regulators that stimulate the growth and
division of cells
 Embryonic development and wound healing.
Apoptosis
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Programmed cell death
Plays a role in development in shaping structuresfingers.
Cancer
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Uncontrolled cell growth
Absorbs nutrients needed by other cells, blocks
nerve connections, and prevents organs from
functioning.
Tumor
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Mass of cells from uncontrolled growth
Benign tumor
 Noncancerous, does

not spread
Malignant tumor
 Cancerous, invades
and
destroys surrounding tissue

Metastasis
 Spread
of cancer cells.
Causes of Cancer

Defects in genes that regulate cell growth and
division
 p53
gene defect is common, doesn’t respond to
growth signals
 Normally many defects or mutations are needed

Sources of gene defects
 Smoking
tobacco, radiation exposure, defective genes,
and viral infection.
Cancer Treatments

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Tumors can be removed by surgery
Tumors treated with targeted radiation
Chemotherapy
 Use
of compounds that kill or slow the growth of
cancer cells.
The Rise and Fall of Cyclins
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
Scientists measured cyclin levels in clam eggs as
the cells went through the cell cycle. The data is
shown on the following slide.
Cyclins are continually produced and destroyed.
Cyclin production signals cells to enter mitosis and
their destruction signal cells to enter interphase.
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Interpret Graphs How long does cyclin production
last during a typical cell cycle in clams
Infer During which part of the cell cycle dose cyclin
production begin and how quickly is it destroyed
Predict Suppose that the regulators that control
cyclin production are no longer produced. What
are two possible outcomes