What are the differences between PCR and DNA replication?

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Accepted Answer

PCR and DNA replication are two processes responsible for DNA synthesis. These are the key differences between the two processes:

Basic of Comparison
PCR
DNA Replication

Definition
Is a laboratory process used to make many copies of a target DNA region 
Is a biological process of producing two identical DNA replicas from one original DNA molecule

Occurence
Is an in vitro process that occurs inside a test tube
Is an in vivo process that occurs inside living cells

Object
To generate many copies of a single DNA fragment
To copy the entire genome at once

Steps involved
Denaturation, primer annealing, and strand extension
Initiation, elongation, and termination

Temperature at which the process occurs
Occurs at three different temperatures inside a machine
Occurs at body temperature within the body of living organism

Polymerizing enzyme
Uses thermophilic DNA polymerase such as Taq polymerase, which operates at high temperatures of 72 °C but has no proofreading ability 
Uses DNA polymerase, which operates at physiological temperature of 37 °C and has proofreading and repair abilities

Primers used
Uses DNA primers
Uses RNA primers synthesized by RNA primase

Denaturing of the Double-Strands
Double strands are separated by applying a high temperature 
Double strands are separated by the enzyme DNA helicase

Continuity and speed of synthesis
Discontinuous process which proceeds through 30-40 cycles at a speed of 1-4 kb/min
Continuous process, which proceeds at a speed of 1 kb/s

Complexity of process
Simple process for in vitro DNA synthesis 
Complex process that is dependent on a well-defined, complex set of enzymes and co-factors

Accuracy/Error rate
Error rate of Taq polymerase in PCR is 1 in 9000 bases
Error rate of DNA polymerase in DNA replication is 1 in 100,000 bases

Basic of Comparison	PCR	DNA Replication
Definition	Is a laboratory process used to make many copies of a target DNA region	Is a biological process of producing two identical DNA replicas from one original DNA molecule
Occurence	Is an in vitro process that occurs inside a test tube	Is an in vivo process that occurs inside living cells
Object	To generate many copies of a single DNA fragment	To copy the entire genome at once
Steps involved	Denaturation, primer annealing, and strand extension	Initiation, elongation, and termination
Temperature at which the process occurs	Occurs at three different temperatures inside a machine	Occurs at body temperature within the body of living organism
Polymerizing enzyme	Uses thermophilic DNA polymerase such as Taq polymerase, which operates at high temperatures of 72 °C but has no proofreading ability	Uses DNA polymerase, which operates at physiological temperature of 37 °C and has proofreading and repair abilities
Primers used	Uses DNA primers	Uses RNA primers synthesized by RNA primase
Denaturing of the Double-Strands	Double strands are separated by applying a high temperature	Double strands are separated by the enzyme DNA helicase
Continuity and speed of synthesis	Discontinuous process which proceeds through 30-40 cycles at a speed of 1-4 kb/min	Continuous process, which proceeds at a speed of 1 kb/s
Complexity of process	Simple process for in vitro DNA synthesis	Complex process that is dependent on a well-defined, complex set of enzymes and co-factors
Accuracy/Error rate	Error rate of Taq polymerase in PCR is 1 in 9000 bases	Error rate of DNA polymerase in DNA replication is 1 in 100,000 bases

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