What is the purpose of a polymerase chain reaction (PCR)? Please provide an example of when you've run one in the past.
PCR is a fundamental technique used in many fields, including medical research and diagnosis, forensic science, and biotechnology. Understanding the purpose and basic principles of PCR is essential for anyone working in these fields. Your interviewer will likely ask various knowledge-based questions to know how well you understand the concept and can explain it to others. Additionally, the interviewer is interested in learning how you have run one in the past, as this can provide valuable insight into your skills and experience.
"PCR stands for Polymerase Chain Reaction, a technique used to amplify a specific DNA sequence. The process involves repeatedly heating and cooling a reaction mixture containing DNA, primers (short DNA sequences that bind to the target sequence), and a particular enzyme called Taq polymerase. This enzyme copies and extends the primers, creating new DNA strands that match the target sequence.
In the past, I have run PCRs using a thermal cycler machine, which is programmed to control the temperature cycles needed for the reaction. I carefully prepared the reaction mixture, including optimizing the concentration of primers and DNA template, and followed the thermal cycling protocol to ensure the successful amplification of the target DNA. It is essential to maintain sterile conditions and prevent contamination during PCR, as even a tiny amount of foreign DNA can affect the accuracy of the results. Overall, PCR is a powerful tool in molecular biology that allows researchers to generate large amounts of specific DNA sequences for further analysis."