What is the primary function of PCR in molecular biology?

The primary function of polymerase chain reaction (PCR) in molecular biology is to rapidly amplify short regions of DNA in vitro. This technique allows researchers to take a small sample of DNA and amplify it many times over, resulting in millions of copies of that specific DNA segment. This is especially useful in situations where only a tiny amount of DNA is available, such as in forensic analysis, genetic testing, or research where a specific gene needs to be studied in detail.

PCR operates through a series of temperature changes that allow for the denaturing of DNA, annealing of primers, and extension by DNA polymerase, facilitating the exponential amplification of the targeted DNA region. Its efficiency and speed have made it an essential tool in molecular biology, diagnostics, and various applications in research fields.

The other options describe processes that either do not accurately reflect the function of PCR or pertain to different techniques. Isolation of RNA from proteins pertains to techniques like extraction and chromatography, sequencing relates more to methods such as Sanger sequencing or next-generation sequencing, and protein synthesis is achieved through transcription and translation processes rather than PCR.