CAIE A Level Biology 9700 · Genetic technology
A forensic scientist has extracted a small quantity of DNA from a crime scene. To obtain enough DNA for analysis, she intends to amplify a specific region using the polymerase chain reaction (PCR). Describe the stages that occur during one cycle of PCR and the role of Taq DNA polymerase in this process.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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