Printed Page 285(cont.)

recap

13.5 recap

Knowledge of the mechanisms of DNA replication led to the development of a technique for making multiple copies of DNA sequences.

learning outcomes

You should be able to:

  • Explain the purpose for each step in the PCR process.

  • Explain why PCR is useful in different research scenarios.

1.

What is the role of primers in PCR?

Primers in PCR bind to a short region of DNA and allow elongation of that strand of DNA when DNA polymerase is added along with nucleotide.

2.

One way to quickly identify an organism in the field is to use PCR: If there is amplification of a particular sequence, then the organism is identified. What is the basis for this test?

If a primer has a species-specific sequence—that is, a sequence of nucleotides complementary to a sequence unique to a certain organism—PCR will amplify a target DNA extracted from a field sample that has the unique sequence. This amplification will show that the organism with that sequence is present