What is the PCR technique used for?

The polymerase chain reaction (PCR) technique is primarily used to amplify specific DNA sequences for analysis. This amplification process allows for the production of millions of copies of a particular DNA segment from a small initial sample. PCR is a critical tool in various applications such as genetic research, forensic analysis, and medical diagnostics, enabling scientists to analyze DNA sequences more easily and accurately.

The technique involves repeated cycles of denaturation, annealing of primers, and extension by DNA polymerase. This results in the exponential increase of the target DNA, making it detectable and usable for further studies such as sequencing, cloning, or detection of mutations.

Other choices represent different biological techniques. For instance, culturing bacteria refers to growing bacteria in a nutrient medium, which is fundamentally different from the molecular amplification provided by PCR. Visualizing proteins is related to techniques like Western blotting or ELISA, while extracting RNA involves methods like phenol-chloroform extraction or using specialized kits, neither of which are associated with PCR.