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GENETICS

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 Control. Gene expression controlled by: Using promoters— sections of DNA that bind RNA polymerase to make mRNA

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GENETICS

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  1. GENETICS Gene Control, Cancer and Genetic Techniques

  2. All cells have the same DNA, but not all cells produce the same proteins; how does this happen?

  3. Gene Control • Gene 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

  4. Cancer • Uncontrolled, abnormal cell division • Cancer can be caused by genetic factors, environmental factors, or a combination of both

  5. Oncogene • A gene that causes a cell to become cancerous • A gene can become an oncogene in 3 ways: • 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

  6. Tumor Suppressor Gene • 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

  7. Carcinogen & Mutagen • 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)

  8. Reducing Cancer Risk • Screening tests such as mammograms, Pap smears and prostate screenings should be done • Healthy behaviors: • Avoid smoking • Eat a low fat diet • Eat a high fiber diet • Use sunscreen

  9. DNA Fingerprinting • 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

  10. Uses for a DNA Profile • Tissue Matching: used to match crime scene evidence to a suspect or to help identify a body • Inheritance Matching: used to determine paternity

  11. Tissue Matching Example • The two samples must have the same band pattern

  12. inheritance Matching Example • Each band in a child’s DNA fingerprint must be present in at least one parent

  13. Creating a DNA Fingerprint • Extraction: DNA must be removed from the nucleus of the cells

  14. Creating a DNA Fingerprint (cont.) • Restriction Fragments: Restriction enzymes are used to cut apart the DNA at specific sites

  15. Creating a DNA Fingerprint (cont.) • Amplification: Polymerase Chain Reaction (PCR) generates multiple identical copies from trace amounts of DNA

  16. Creating a DNA Fingerprint (cont.) • 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

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