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Victoria Police forensic scientists conduct DNA profiling using samples taken from crime scenes - VCE - SSCE Biology - Question 2 - 2007 - Paper 1
Question 2
Victoria Police forensic scientists conduct DNA profiling using samples taken from crime scenes. Traces of DNA of less than 1 nanogram can be amplified and then prof... show full transcript
Worked Solution & Example Answer:Victoria Police forensic scientists conduct DNA profiling using samples taken from crime scenes - VCE - SSCE Biology - Question 2 - 2007 - Paper 1
Step 1
Step 2
b. What must be done between stages 1 and 2 to separate the strands of the DNA molecule?
Answer
In order to separate the strands of the DNA molecule between stages 1 and 2, heating the DNA to 90°C or greater must be performed. This heating is necessary to break the hydrogen bonds that hold the two strands together.
Step 3
c. Complete and label the diagram at stage 2.
Answer
In the diagram:
- Primers attach at the 3' end of the strands.
- The temperature is reduced to approximately 50°C to allow the primers to anneal.
- DNA Taq polymerase is added to extend the new strands from the primers, occurring away from the primer ends.