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Molecular Genetics
Quick questions on DNA technology and applications: H2 Biology Molecular Genetics
5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is the polymerase chain reaction (PCR)?Show answer
PCR copies a target sequence in a tube through repeated cycles of three temperature steps: denaturation (about 95 degrees, strands separate), annealing (about 55 degrees, primers bind), and extension (about 72 degrees, a heat-stable DNA polymerase builds new strands). Each cycle doubles the target, so many cycles give millions of copies.
What is dNA sequencing?Show answer
Sequencing reads the exact base order of a DNA sample. Modern methods are fast and cheap enough to sequence whole genomes, underpinning genomics.
What is q1?Show answer
State the role of a restriction enzyme in recombinant DNA technology. [1 mark]
What is q2?Show answer
Explain why DNA fragments separate by size during gel electrophoresis. [2 marks]
What is q3?Show answer
State the purpose of the primers used in PCR. [1 mark]
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