PCR, gel electrophoresis and DNA profiling Quiz
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5 questions, one answer each
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1. Why is DNA attracted to the positive electrode during gel electrophoresis?
- A. It contains many hydrogen bonds
- B. Its bases are positively charged
- C. Its phosphate groups are negatively charged
- D. It is bound to histone proteins
2. A PCR starts with one DNA molecule. How many copies are there after 10 cycles, assuming doubling every cycle?
- A. 1024
- B. 100
- C. 20
- D. 512
3. In a PCR cycle, which stage happens at about 55 °C?
- A. Strands separate
- B. Taq polymerase extends the new strands
- C. Fragments are ligated
- D. Primers anneal to the template strands
4. A child has STR bands at a locus of 8 and 13 repeats. The mother has 8 and 10. What can be concluded?
- A. The child has a mutation
- B. The father must have a band of 13 repeats
- C. The mother cannot be the parent
- D. The father must have a band of 8 repeats
5. Four fragments of 150, 900, 2000 and 400 base pairs are separated by electrophoresis. Which stays closest to the well?
- A. 150 base pairs
- B. 900 base pairs
- C. 2000 base pairs
- D. 400 base pairs