Colon Cancer Scenario
Introduction: Gel electrophoresis is an important molecular biology tool: it enables us to study DNA. It can be used to determine the sequence of nitrogen bases, the size of an insertion or deletion, or the presence of a point mutation; it can also be used to distinguish between variable sized alleles at a single locus and to assess the quality and quantity of DNA present in a sample. Gel electrophoresis is a method of separating chemical compounds and molecules by their size and charge. The substances being separated are placed in wells in an agarose gel and subjected to an electrical field. Negatively charged molecules move towards the positive anode, and positively charged molecules move towards the negative anode. Longer or larger molecules have difficulty traveling through the gel; they become entangled in the gel matrix. Shorter or smaller molecules migrate through the agarose matrix faster and thus travel farther in a given time period. Similar sized fragments travel at relatively the same speed and form a tight "band" when stained. Pre-Lab Questions:
DNA fingerprinting is the identification of DNA through the process of gel electrophoresis. PCR is performed in order to amplify a specific section of DNA and is especially helpful when looking for one trait in particular. All possible results are: a) only one child has the gene for colon cancer, b) the twins have the gene for colon cancer c) all of the children have the gene for colon cancer, d) none of the children have the gene for colon cancer. Hypothesis: (See third pre-lab question)
Tape the open ends of the gel tray using masking tape. Run your thumb firmly along the taped edge of the tray to ensure a reliable seal. Insert the well-forming comb in the set of grooves at the end of the tray. Pour...
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