Download GENETICS

Gene Control, Cancer and
Genetic Techniques
All cells have the same DNA,
but not all cells produce the
same proteins; how does this
happen?
 Gene
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expression controlled by:
Using promoters—sections of DNA that bind RNA
polymerase to make mRNA
Using repressors—proteins that bind DNA to turn
off genes
Permanently turning off genes
Control RNA splicing
 Uncontrolled,
abnormal cell division
 Cancer can be caused by genetic factors,
environmental factors, or a combination
of both
A
gene that causes a cell to become cancerous
 A gene can become an oncogene in 3 ways:
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Mutation occurs in a growth-factor gene (a gene that
controls cell division)
Error in DNA replication results in multiple copies of
a single growth-factor gene
A change in a gene’s location
 Gene
responsible for preventing uncontrolled
cell growth
 If a gene mutation occurs in a tumor
suppressor gene so that it does not work
anymore, uncontrolled cell growth could
result
 Carcinogen:
an agent that causes or tends to
cause cancer (ex: UV radiation or tars in
cigarette smoke)
 Mutagen: a factor in the environment that
can cause mutations in DNA (ex: radiation)
 Screening
tests such as mammograms, Pap
smears and prostate screenings should be
done
 Healthy behaviors:
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Avoid smoking
Eat a low fat diet
Eat a high fiber diet
Use sunscreen
 Procedure
that creates a DNA profile
 Because no two people on this earth can
have the same DNA (with the exception of
identical twins), each profile is unique to
each person, like a fingerprint
Tissue Matching: used to match crime scene
evidence to a suspect or to help identify a
body
Inheritance Matching: used to determine
paternity
The two samples must have the same band
pattern
Each band in a child’s DNA fingerprint must
be present in at least one parent
1.
Extraction: DNA must be removed from the
nucleus of the cells
2.
Restriction Fragments: Restriction enzymes
are used to cut apart the DNA at specific sites
3.
Amplification: Polymerase Chain
Reaction (PCR) generates multiple
identical copies from trace amounts of
DNA
4.
Electrophoresis:
In this process, DNA fragments created through
PCR are separated by using an electrical field
DNA is negatively charged and will move
towards a positive electrode
The smaller the fragment, the faster it will
travel