How does pcr differ from dna replication?

Polymerase chain reactions underlie both PCR and in-vivo DNA replication. The main distinctions are as follows:

The PCR reaction uses temperature cycles (with extremes of 70-90C) to cause denaturation and annealing of DNA strands. DNA replication is carried out at body temperature (37C in humans) with the assistance of a complex machinery. for example, helicase unwinds dsDNA, single-strand-binding proteins stabilize these unwound strands, etc.

Type of polymerase: Taq polymerase and other thermostable DNA polymerases derived from bacteria or archaea are used in PCR. Eukaryotes contain a wide variety of DNA polymerases.

Length of DNA: The body regularly replicates whole genomic DNA. The polymerase used in the PCR reaction has a much shorter half-life and is only effective for much smaller fragments of DNA.

PCR reactions use simpler polymerase that are not as "feature-rich"; for example, the widely used Taq polymerase has no proofreading ability. More accurate options are commercially available (ampliTaqGold, PlatinumTaqPolymerase, Pfu DNA polymerase, etc.). High fidelity, speed, proofreading, and repair are desirable features required of DNA replication.

PCR is a laboratory technique to amplify specific DNA segments, typically in vitro, using a heat-stable DNA polymerase and specific primers. DNA replication is a natural cellular process that occurs in living organisms, involving the synthesis of an entire DNA molecule in a cell's nucleus.