BIOL337 Module 3 Worksheet Part 2

BIOL337 Module 3 Worksheet Part 1 (40 pts.) Name: Section 2 Working with DNA Part 1: Extracting DNA (9 pts) 1. What does the DNA extraction simulation list as three reasons that one might need to extract human DNA? Come up with two or more reasons of your own. 2. From where does the DNA extraction simulation acquire the cells for DNA extraction? Is it important to take cells from a particular part of the body because we plan to amplify a gene involved in tasting? 3. What is the purpose of the cell lysis solution? 4. After the first centrifugation step, where is the DNA located? Part 2: Amplifying DNA (9 pts) 5. From where does the PCR simulation acquire the DNA used for the PCR? Could we use DNA from this source to investigate a gene involved in tasting? 6. During “cycle #1” of the simulated PCR, the image shows a “target sequence”. Explain how the DNA polymerase enzyme identifies where the target sequence is located. 7. During each reaction cycle, the DNA is shown “unzipping” prior to duplication. Explain how the DNA strands are induced to separate during the PCR reaction. 8. What is the function of the negative control? If DNA is found in your negative control, what does that indicate about your PCR reaction? Section 3 Collecting DNA Data Part 1: Phenotypes (6 pts) 9. Consider your affinity for broccoli and guess as to your phenotypic category: Strong taster, weak taster, or nontaster. 10. What is your predicted genotype considering your assigned phenotype? 11. What is our null hypothesis regarding the proportion of tasters and nontasters in the class? Part 2: Restriction Digest (6 pts) 12. Describe the expected outcome from a restriction digest of each of the three potential genotypes (AVI/AVI, AVI/PAV, PAV/PAV). In other words, based on the results of the virtual restriction digest, what are the expected fragment sizes resulting from the digestion? Part 3: Electrophoresis (10 pts) 13. Explain the principle of electrophoresis. Why does DNA move when exposed to an electric field? Be specific! 14. Explain why larger fragments migrate more slowly on gels than smaller fragments. 15. Record the position of expected DNA bands on the gel relative to the bands of the ladder (A1). (Copy and paste the orange line segment as needed. It is probably a good idea to group the lines and gel diagram together when you are finished to avoid undesired changes.) • In well A2 record the position of the undigested control (the PCR amplicon) band. • In well A4 record the position of bands predicted from a “strong taster” phenotype. • In well A6 record the position of bands predicted from a “weak taster” phenotype. • In well A8 record the position of bands predicted from a “non taster” phenotype. • In well A10 record the banding pattern you expect from your own phenotype.