Final answer:
PCR is similar to DNA replication in cells as it uses DNA polymerases for nucleotide addition, but it differs by using specific DNA primers, heat-tolerant Taq polymerase, and it repeatedly cycles through steps in a test tube to amplify DNA.
Step-by-step explanation:
PCR, or Polymerase Chain Reaction, is similar to DNA replication in that it uses the same basic principles of DNA polymerases adding nucleotides to a DNA strand. However, the processes have key dissimilarities. PCR involves denaturation, annealing of primers, and extension phases that are repeated cyclically to amplify DNA in a test tube, unlike in the more complex cellular environment with multiple enzymes and regulatory processes.
Unlike in cells where DNA replication is initiated by RNA primers, PCR employs specially-designed DNA primers that target specific DNA sequences. These are synthesized commercially and provide greater stability for the PCR process. Furthermore, PCR uses the enzyme Taq polymerase, derived from the hyperthermophilic bacterium Thermus aquaticus, while cells use a myriad of DNA polymerases that are not heat-tolerant.
This thermal stability is crucial as PCR involves high temperatures that would denature regular enzymes.The purpose of PCR is to amplify a specific DNA sequence millions of times, which can be done in a short amount of time, making it a vital tool in many fields including forensic science and medical diagnostics.