Core Idea Extension
Molecular Biology Lab
PCR, sequencing, cloning, gel electrophoresis, and assays are the practical tools that turn molecular biology concepts into measurable evidence.
Interactive Lab Sequence
Study the Five Core Molecular Lab Methods
Select a method below. The large panel displays the method image across the full frame with an exam-focused explanation written for college-level study.
Molecular Biology Lab
PCR
Amplifying specific DNA sequences
PCR, or polymerase chain reaction, is used when the target DNA is present in a tiny amount but must be copied enough times to analyze. The exam idea is simple: denature the DNA strands, let primers anneal to the target region, and extend new strands with DNA polymerase. Repeating those temperature cycles creates exponential amplification, so one chosen sequence becomes millions to billions of copies. PCR is high specificity because primers define the target, sensitive because very small starting quantities can be detected, and rapid because cycling can be completed quickly. In clinical and research settings, PCR supports pathogen detection, variant testing, gene expression workflows after reverse transcription, forensic analysis, and preparation of DNA for sequencing or cloning.