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Cell cycle, mutation, cancer, and
Natural selection
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Learning objectives
Explain the impact of point mutations and how they can
modifygenes and produce changes in phenotypes.
What types of mutations can lead to cancer? Give some
examples.
Describe how the gene BRAFis involved in the regulation of the
cellcycle
Describe how the molecule vemurafenib is used in the treatment
ofmelanoma
Describe how the protein MPF is involved in the regulation of
thecell cycle
Explain the consequences of uncontrolled cell division, and
howgrowth factors are involved in control of the cell cycle
Diagram how selection could lead to proliferation of
malignantcancerous cells.
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Summary Table 16.1
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Figure 16.9. Chromosomal level mutations. A karyotype from a
breast cancer cell. Normally
each chromosome would be stained the same color and each
chromosome type would be
represented by two chromosome.
22212019 X Y
181716151413
6 7 8 9 10 11 12
54321
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Mitosis-promoting factor (MPF)
Cyclin is a
regulatoryprotein
Cyclin-dependent
kinase (Cdk) catalyzesphosphorylation of other
proteins to start mitosis
Cyclin Cdk
MPF Cdk
MPFcomponentconce
ntration
Time
Figure 12.11
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Figure 12.12 Slide 6
Mitosis
Firstgap
G2checkpoint
G1checkpoint
M-phase checkpoints
Mature cells do notpass this checkpoint(they enter G0state)
Pass checkpoint if:
Pass checkpoint if:
Pass checkpoints if: chromosomes have
replicated successfully DNA is undamaged
activated MPFis present
cell size is adequate nutrients are sufficient social signals
are present
DNA is undamaged
1.chromosomes haveattached to spindleapparatus
2.chromosomes haveproperly segregatedand MPF is absent
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(a) Benign tumor
Normal cells
Blood vessel
enign tumor cells
may continue to
divide, but are not
invasive (they do not
spread from tumor)
Lymphatic vessel
Figure 12.14
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(b) Malignant tumor
Malignant tumor cells
divide and spread toadjacent tissues and to
distant tissues through
lymphatic vessels and
blood vessels
Lymphatic vessel
Blood vessel
New tumor that has
formed in distant
tissue by metastasis
Figure 12.14
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One general common characteristic of the most
serious cancers might be ________.
A. the ability of defective cells to drain surrounding
cells or tissues of nutrients
B. the speed at which defective cells divide
C. the ability of defective cells to relocate to
other tissues
D. the location of the cancer
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10/14 2014 Pearson Education, Inc.
One general common characteristic of the most
serious cancers might be ________.
A. the ability of defective cells to drain surrounding
cells or tissues of nutrients
B. the speed at which defective cells divide
C. the ability of defective cells to relocate to
other tissues
D. the location of the cancer
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Growth
factors
1. Growth factors
arrive from other
cells.
2. Growth factors
cause increase in
cyclin and E2F
concentrations.
3. Cyclin binds to
Cdk; Cdk is
phosphorylated.
Rb inactivates E2F
by binding to it.
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4. Cdk is activated
by dephosphorylation.
It catalyzes
phosphorylation of Rb.
5. Rb releases
E2F.
6. E2F enters
nucleus and
triggers production
of S-phase proteins.
G1checkpoint
passed
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The BRAF pathway
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