small sample of DNA was obtained from a fossil - VCE - SSCE Biology - Question 29 - 2020 - Paper 1
Question 29
small sample of DNA was obtained from a fossil. Polymerase chain reaction (PCR) was used to amplify the amount of DNA obtained from the sample.
Which one of the fol... show full transcript
Worked Solution & Example Answer:small sample of DNA was obtained from a fossil - VCE - SSCE Biology - Question 29 - 2020 - Paper 1
Step 1
DNA polymerase catalyses the pairing of primers with complementary nucleotides.
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Answer
This statement is incorrect. DNA polymerase is responsible for adding nucleotides to the growing DNA strand, not for pairing primers.
Step 2
RNA polymerase catalyses the additions of nucleotides to a DNA strand.
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Answer
This statement is incorrect. In PCR, DNA polymerase, not RNA polymerase, catalyzes the addition of nucleotides to form the new DNA strands.
Step 3
Annealing and extension of the DNA occur at different temperatures.
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Answer
This statement is correct. In PCR, annealing occurs at a lower temperature to allow primers to bind, while extension occurs at a higher temperature for DNA polymerase activity.
Step 4
The number of copies of the DNA is quadrupled in each cycle.
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Answer
This statement is correct. Each cycle of PCR typically doubles the amount of DNA, and with multiple cycles, the amount can be mathematically represented as quadrupling for the second cycle.
