Q4 · 2021 · Paper 2Unclassified2 marks
QUESTION 4 (2 marks)
Explain the purpose of the polymerase chain reaction (PCR) process and provide an example of its application.
WORKED SOLUTION
2 marksQCAA guide · typeset solution
QCAA sample response and mark allocation
4 | Polymerase chain reaction is used to amplify (i.e. make many copies) of a DNA template because usually only a small amount of DNA is available for analysis. For example, crime scene DNA is sometimes found only at trace levels. PCR amplifies this small amount to allow analysis to be carried out. | • explains purpose of PCR as amplifying a DNA sample for further analysis [1 mark] • provides an example [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
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