What is PCR and what are its basic components?

PCR (Polymerase Chain Reaction) is a technique for amplifying specific DNA sequences exponentially. The basic components are: template DNA containing the target sequence, two primers (short oligonucleotides) flanking the region to amplify, thermostable DNA polymerase (Taq), dNTPs (nucleotide building blocks), and buffer with MgCl2. The process involves three repeated steps: denaturation (94-95C, separating strands), annealing (50-65C, primer binding), and extension (72C, DNA synthesis). Each cycle doubles the target DNA, producing millions of copies from minimal starting material within hours.